NATIONAL 
STEEL LUMBER 

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H ANDBOOK of 

National Steel Lumber 

PRODUCED BY 

The National Pressed Steel Co. 

t( 

Main Office and Works 
Massillon, Ohio 


Copyright, 1921 

By The National Pressed Steel Co. 
Massillon, Ohio 


Prepared by 

The Steel Lumber Division 

under the direction of 

H. M. NAUGLE 
STANLEY MACOMBER 


Atlanta 

Baltimore 

Boston 

Chicago 


DISTR ICT OFFICES 

Cleveland 

Dallas 

Detroit 

Indianapolis 


Kansas City 
Minneapolis 
New York 
Philadelphia 


Distributors in all principal cities 













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ERIT is largely a question of comparison. Therefore 
to visualize more clearly the efficiency and practica¬ 
bility of Steel Lumber construction it is proper to compare 
it with other accepted types of fire-safe designs. Con¬ 
siderable space is given in this handbook to the consider¬ 
ation of costs of construction—-attention being directed to 
conditions that affect the total costs of the structural part 
of a building. 

In order that the Architect and Engineer may more 
readily grasp the efficiency of Steel Lumber and the effect 
of its use on other portions of the building various com¬ 
parisons are drawn. Let it be understood that these 
comparisons are not made with any spirit of criticism, but 
for the purpose of securing a better understanding as to 
the particular field in which a type of construction is the 
most practical. 

Good engineering calls for the use of those materials 
which under given conditions will most efficiently and 
economically meet the requirements. There is no ma¬ 
terial nor any one type of construction that universally 
proves the best. The proper combination of materials 
structurally and otherwise requires special and intelligent 
study. 

Confidence in the practicability and durability of steel 
construction is derived from a thorough understanding of 
the action of steel under high temperatures. Such infor¬ 
mation is presented in this book and the difference between 
structural and National shapes is pointed out. The rela¬ 
tive efficiency of the two products and the requisite fire 
protection required for each is discussed. 


Cl A620092 




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I 



Notice 

I N this second edition of the National Steel Lumber 
Handbook is embodied complete information and 
authentic data pertaining to the use of Steel Lumber 
Sections and kindred materials. 

The last two years have witnessed a remarkable in¬ 
crease in the tonnage of Steel Lumber Sections installed 
throughout the country. Experience during this time has 
developed a number of improvements in the product. 
Some changes have been made in the design of National 
Sections resulting in greater efficiency. The Spring Lath 
Clip has provided a firmer bond between lath and joists, 
simplified distribution and reduced installation costs. 
This edition of the Handbook covers all recent develop¬ 
ments and. amplifies in many respects the contents of the 
first edition. 

The first edition of the National Steel Lumber Hand¬ 
book was founded upon data compiled during a period of 
twelve years by the individuals who conceived the idea 
of Steel Lumber and developed the product throughout 
the engineering, manufacturing and installation stages. 
This second edition has been prepared by an organization, 
manufacturing on a mill basis in large quantities and long 
lengths and distributing over every portion of the United 
States. 

Steel buildings, as developed through the use of struc¬ 
tural steel skeleton frame supporting Steel Joist floors, are 
rapidly proving their superiority in every respect over all 
other known types of fire-safe construction. The leading 
steel fabricating interests throughout the country advo¬ 
cating this type of structure and rendering designing 
service recognized as of the highest standard, form a 
responsible distributing unit upon which the building 
public can depend with absolute confidence. The dealer 
organization developing around the fabricating industry 
is carrying the availability of steel construction into every 
community and for all classes of buildings, large and 
small. 

Stocks of National Steel Lumber, structural steel and 
steel lath have been established in all principal distributing 
centers to insure prompt deliveries and facilitate the 
maintenance of a high standard of service. 



Preface 

Steel Lumber was designed primarily to take the place 
of wood joists and studs in floor and partition construction. 
The use of steel lath, which is secured to the steel sections 
by means of spring lath clips attached over the flanges, 
provides a construction which entirely eliminates com¬ 
bustible material. The result is a light weight, fireproof 
and indestructible building at slightly increased cost over 
that of wood. 

The value of this material in reducing the enormous 
annual fire losses and the economic necessity of bringing 
the cost of fireproof construction within the range of the 
average individual have been evidenced by the rapid and 
substantial growth of the demand for Steel Lumber. 

In order to supply this increasing demand we installed 
special mills, machinery and equipment to the extent that 
sufficient quantity, proper quality and service are assured. 

National Steel Sections are the result of intimate first¬ 
hand knowledge of the Steel Lumber industry. In every 
respect they are so designed as to develop the greatest 
efficiency and economic advantage. The salient points of 
every phase of the industry have been given full consider¬ 
ation. The result is a co-ordination of the various features 
applying from every angle in a section design that is basic 
in its economy and efficiency. 

The process oi manufacturing the steel and forming 
the product as embodied in our plant is the best that 
engineering ability and mechanical facilities have produced- 
The analysis and working of the steel are such that the 
greatest advantages are secured in quality and strength. 

The information presented in tms handbook is intended 
as a real aid to the architect and engineer in economically 
designing buildings by using National Steel Lumber. 
Information regarding standard sections only is given but 
special shapes can be produced at small additional cost. 



TABLE OF CONTENTS 

Page 

Notice . 3 

Preface. 4 

National Steel Lumber. 5 

Strength of Steel at High Temperatures 6-7 

National Steel Joist Development and 
Comparison. 8-11 

National Steel Lumber Sections. 12-20 

Accessories..... 21 

Designing Data. 22 

Safe Loading Tables..... 23-35 

Beam Clips. 36-37 

Beam Furring Clips... 38-39 

Steel Lath. 40-43 

Spring Clips... 44-48 

Bridging. . 49-53 

Installing Steel Joists.. 54-55 

Estimating Data. 56-62 

Economy of Steel Construction. 63 

Cost Data. 64-73 

Construction Details... 74-101 

Stairway Construction.102-105 

___ 






















TABLE OF CONTENTS 

Page 

r 

Fireproofing of Structural Steel.106-110 

Footing Design.111-115 

Comparisons of Dead Weight.116-119 

Specifications ..-.120-124 

Framing Openings.....125-127 

Garage Floors... 128 

Strength of Slab on Joists. 129 

Weight of National Steel Lumber Floors 130-131 

General Information... 132-148 

Various Uses of Steel Lumber__149-155 

Live Loads.156-157 

Bending Moments and Formulae..158-159 

Weights of Building Materials. .160-161 

Coefficients of Deflection.. 162 

Safe Unit Fibre Stress... 163 

Structural Timber. 164-168 

National Strip Steel. 169 

Gauge Equivalents. 170 

National Steel Lumber Distributers. 180 

\ 

(For Complete Detail of Contents, see Index) 


L 






















THE NATIONAL PRESSED STEEL COMPANY 


National Steel Lumber 

'^TATIONAL Steel Lumber is made from a high quality 
^ basic open hearth steel, rolled from a slab to the finished 
product in our own mills under strict supervision and 
inspection. 

These sections can be furnished in maximum lengths 
of one hundred feet if desired, thus eliminating all splicing. 
As the strips receive even rolling and are of uniform thick¬ 
ness over the entire width, they come from the mill 
perfectly flat showing the absence of internal stresses. 

After the strip is thoroughly cooled, it is then formed 
into the section, which insures uniformity throughout, 
and which uniformity eliminates the possibility of dis¬ 
tortion due to internal stress if subjected to high temper¬ 
ature. On account of the uniformity of the thickness of 
the section and the uniformity of the steel contained 
therein, a maximum strength is obtained at comparatively 
high temperatures. Actual fire tests have proven this and 
show the superior merits of Steel Lumber for fireproof 
construction. 

The strength of National Steel Joist is ample for the 
purpose intended—all tables being computed on the basis 
of a safety factor of 4 with a fibre stress of 16,000 lbs. 
per square inch. The manufacturing processes that give 
the joists a greater fibre strength and uniformity are not 
adapted to the production of heavy sections such as are 
found in structural steel. The function of the steel joist 
is to pick up the floor loads of buildings, and when such 
loads have reached a sufficient total transfer them to the 
heavier sections comprising the skeleton frame or to 
supporting walls. 

The success of Steel Lumber is based upon: fire proof 
qualities—sound proof qualities—low cost—simplicity of 
design and installation—adaptability—durability—ease of 
inspection—light weight, and rapidity of erection. 


5 





Temperature-Strength Curve-Low Carbon Steels 

As used in Structural and National Shapes 


THE NATIONAL PRESSED STEEL COMPANY 





6 


Temperature in degrees Fahrenheit. 

































































































































THE NATIONAL PRESSED STEEL COMPANY 

Strength of Steel at High 
Temperatures 

The use of iron and steel is universal. No other metal contributes 
so much to the welfare and comfort of man. No other metal is capable 
of giving the great range in physical properties that makes iron avail¬ 
able for so many purposes. Different methods of production and the 
changing of alloy contents produce finished steels of entirely different 
physical properties and available for widely different purposes. Daily 
contact with some articles of steel composition has familiarized the 
layman with the nature of this metal. The superior quality of a 
refined steel as used in a razor blade is recognized and understood. 
Other metallurgical principles such as the action of steel under high 
temperatures are not generally known. Referring to building con¬ 
struction where steel is commonly used it is proper that the results of 
different production methods and the action of different steels under 
possible temperature conditions should be thoroughly analyzed. 

The different methods used in producing National and structural 
sections are described on pages 5 and 132. The result is an ultimate 
strength in the structural section of approximately 55,000 lbs. per sq. 
inch and in the National Sections exceeding 70,000 lbs. per sq. inch 
The extra working of material which greatly refines the steel fibre in 
National Sections raises the elastic limit to relatively a much higher 
point. 

On page 9 the different actions of National Steel Lumber and Rolled 
Structural Shapes when subjected to high temperatures is discussed. 
The next point of interest is the relative strength of steel under these 
conditions. The curves, page 6, graphically illustrate the change in 
strength under changing temperatures. 

Although steel of the structural grade has a greater ultimate strength 
at temperatures around 700° F., structural shapes because of their 
process of production tend to twist and distort under that condition. 
For that reason it is necessary to provide ample fire protection (IK to 
2" of concrete or cement plaster on steel lath) for maintaining the 
temperature around the sections below that danger point. 

With Steel Lumber ample strength is available up to temperatures 
around 1000° F. to 1200° F. with no tendency to twist or distort, 
therefore the same amount of protection is not required. 

Only a very small percentage of fires develop temperatures exceed¬ 
ing 1200° F. to 1500° F., but the designer must take into account the 
unusual condition. Repeated fire tests have proven that K" of cement 
ceiling plaster will protect Steel Joist floor construction against temper¬ 
atures as high as 1700° F., such condition developing less than 550° F. 
around The joists. This temperature is amply safe even for structural 
sections but because of the greater responsibility and lower danger 
point columns should always be more heavily protected. The same 
being true of main supporting girders in higher buildings. 


7 




THE NATIONAL PRESSED STEEL COMPANY 


National Steel Joist Development 
and Comparison 

Discussing Fig. 1, a wood joist, we have a section 
which has been used effectively from a standpoint of 
strength and adaptability, but not from the standpoint 
of an economical use of material. The wood joist proves 
low in cost, only on account of its ease of production, but 
this condition is rapidly changing, and the wood joist 
is becoming more expensive and questionable in quality. 
If the wood joist could be substituted by a plate of steel 
placed on edge, at the same strength but less weight, 
efficiency would be readily admitted. This is substantially 
what has been done in producing National Steel Joists, 
excepting that flanges have been added to produce lateral 
stiffness, serve as a means of fastening finished floor 
and ceiling to the joist section, and contribute additional 
strength. 

An analysis of the wood joist shows that the tension, 
compression and shearing stresses are resisted entirely 
by what might be termed a web section, or what corre¬ 
sponds to the web section of a steel joist ora rolled steel beam. 

Referring to Fig. 2, the rolled steel beam of equal 
depth performs its function in a different way than the 
wood joist. The top flange, bottom flange and web are 
designed to resist the compression, tension and shearing 
stresses respectively. 

In producing the standard rolled steel section, it is 
impossible to have every portion of the steel making up 
the section receive the same amount of rolling. This is 



Fi &. 1. Fig. ? Fig. 3 


8 
























THE NATIONAL PKESSED STEEL COMPANY 


because of the horizontal groove rolls employed in the 
old style shape mills. 

When this shape comes from the rolls, finished as to 
size, and naturally of comparatively high temperature, it 
is very crooked and must be run through straightening 
rolls in the cooling process. This straightening is made 
necessary by the deformation caused by unequal expan¬ 
sion and contraction due to the varying thickness and 
unequal density of material making up the section. 
The web is the only part of the section properly rolled in 
the mill, the flanges being produced by crowding or 
dragging the metal through the flanged grooves of the rolls. 

Since this condition of internal stress is produced 
originally by temperature reactions through cooling, it is 
natural that a similar condition will prevail when the 
section is again subjected to a high temperature for the 
latent stresses in the section, created in the process of 
straightening, are released, causing deformation and dis¬ 
tortions until the stresses in the steel are either in equilib¬ 
rium or the beam fails. Invariably the primary cause of 
failure of rolled steel beams in buildings subjected to 
fire is due to internal stress caused by excessive temperature 
being applied to either the top or bottom flange, or both. 
Therefore, the necessity of totally incasing a rolled steel 
beam with tile, metal lath and plaster, concrete or some 
other protective fireproof material. 

An analysis of the rolled steel beam (Fig. 2) 
will show that the flanges contribute 44% each of 
the resisting inches or section modulus, while the web 
contributes only 12%. Since the bottom flange is the one 
most likely to be subjected to excessive temperature, and 
since this flange is required to resist tension stresses, it is 
the practice to provide approximately 2 inches of fireproof 
protection. 

A careful analysis of Fig. 3, illustrating a National 
Steel Joist, shows a different condition prevailing. The web 
contributes a large percentage of the resisting inches or 
section modulus. In the case of the National Steel Joist 
the web contributes 40%, the flanges 30% each. It is 
readily seen that the bottom flange is not of such import¬ 
ance as is the case with the rolled steel beam. The pro¬ 
tection of the flange with approximately J^-inch of plaster 
produces a result which is equal to the protection of a 
rolled steel beam with 2 inches of fire-proof material. In 
addi ion to this the National Steel Joist is free from internal 
stresses due to unequal rolling and thickness, and conse- 









THE NATIONAL PKESSED STEEL COMPANY 


quently will not twist and distort under high temperatures. 
By application of the floor and ceiling to the flanges of 
the joist the web is surrounded by a dead air space, which 
is the best method of insulation. 

Other Points of Merit 

»» 

Steel Joist construction provides a first-class fire¬ 
proof building with the lightest floors, and so reduces 
dead load weight on beams, columns, walls and founda¬ 
tion. 

It is sound proof, making it ideal for installation in all 
classes of buildings. 

It gives a finish in a building not obtainable in many 
other types of fireproof construction. Plaster is mechan¬ 
ically bonded to the metal lath and becomes a permanent 
part of the building. 

It provides a safe and dependable means of economical 
construction during winter months; the prosecution of 
the work not being handicapped by usual protective 
measures, and the danger of serious results from freezing 
being entirely eliminated. 

The more simple a construction the less is the chance 
for failure. Steel Joist construction is the most simple 
of floor constructions. It is consequently the most 
reliable. The joists provide the entire carrying capacity 
of the floor panel; dependence not being placed on a 
combination of a number of different materials to develop 
the total required strength. Steel joists can be erected 
safely and quickly with very little supervision and inspec¬ 
tion, whereas with all other fireproof systems skilled 
supervision and inspection is required. The accuracy of 
placing the steel is not simply a point of good workman¬ 
ship, but a matter of vital importance as regards the actual 
strength and carrying capacity of the structure. 

It has always been recognized that the ideal building 
material, whether for beams, girders, floors or columns, 
is a shop fabricated material; that the custom of using 
loose bars with the attendant necessity of dependence 
upon the human element was wrong in principle and 
dangerous in action. All attempts, however, to supply 
the proper construction for floors, whose members were 
properly fabricated in advance, have proved failures 
commercially owing to the excessive cost of fabrication, 
and the impossibility of shipping the ordinary flimsy 
fabricated units without serious damage in transit, and 


10 




THE NATIONAL PKESSED STEEL COMPANY 


the excessive cost of erection, until the idea and applica¬ 
tion of steel joist construction was successfully worked out. 

A perfect floor construction must be one whose separate 
integral parts will satisfy the following conditions:— 
The integral parts must be technically correct, and the 
units made up of these parts must be rigid in construction, 
and so designed that every detail and part of the con¬ 
struction will automatically and without dependence upon 
skill or care, take and hold, under all conditions, its proper 
place in the construction — it must be adaptable to its 
specific purpose in the construction — it must be a 
construction whose safety is not dependent upon the 
personal equation. Weather changes and their attendant dis¬ 
comforts should not affect the reliability of the construction. 

These points are all met by National Steel Lumber 
construction. It is a unit system in its fullest sense. 
Each and every joist is a unit of the floor and entirely 
supports the loads superimposed thereon. A National 
Steel Joist floor is one that supports all the varied stresses 
with individual units. 

Heavy or intricate members are absent in National 
Steel Joist floors. There are no loose parts to get lost, no 
work requiring the services of those having previous 
experience in handling this material. The joist is an 
entire unit in itself, it is solid, self contained and rigid, and 
is in every way a rugged, practical, workmanlike device 
to do just one thing and do it well with the least amount 
of assistance. 

Strength of Standard Steel Joist Floors 

It is interesting to note that because of the high 
ultimate strength and elastic limit of the steel in National 
Steel Joists that the finished floor construction will carry 
without undue deflection much heavier loads than con¬ 
templated in design. Many authoritative loading tests 
have been made, and in every instance it takes at least 
two and one-half times the designed live load super¬ 
imposed on the standard floor construction to develop a 
maximum deflection equal to 1/360 of the net span. For 
testing to failure a load at least eight times the designed 
load will be required. 


11 




THE NATIONAL PRESSED STEEL COMPANY 


National Steel Lumber Sections 

National I Joists are symmetrical in section. The 
flanges are uniform in thickness and one-half the thickness 
of the web. Heavier sections are obtained by increasing 
the thickness of material used. Weights shown \are 
minimum and for standard sections. Special sections both 
as to weight and shape can be produced by special arrange¬ 
ment. 

The particular field for Steel Lumber construction is 
in buildings designed for medium live loads. The dimen¬ 
sions and weights of the joist sections have been worked 
out to provide the most efficient and practical design for 
that purpose, experience having demonstrated that in 
every respect the standard sections provide sufficient 
latitude for all variations in loading conditions. 

Flange widths are held well within the limits which 
insure full working stress of all parts of the section. 
Thickness of material is increased with the depth of 
section, as experience and repeated tests have proven that 
this is necessary in order to maintain the same high degree 
of efficiency in all siz”. 

For convenience in identification and specifying, sec¬ 
tions are designated by their depth and weight, i. e., 

10"—8.7 lb. I 
4"—1.85 lb. C 

All sections are given a dip coat of paint before leaving 
the mill. The National base covers painted sections, mill 
delivery, cut for stock with a two-foot tolerance in length 
of sections. Maximum lengths being controlled by ship¬ 
ping facilities. 

Lengths will be cut to a tolerance (for specification) 
at an extra cost. 

Sections are furnished only on catalog weights and to 
an allowable variation of from published weights. 

Accessory items such as Bridging, Beam Clips, Furring 
Clips and Spring Lath Clips have been designed to sim¬ 
plify and improve the construction and are shown on 
page 21. They are required on practically every installa¬ 
tion and are carried in stock in ample quantities at all 
distributing points. 


12 





13 





























THE NATIONAL PRESSED STEEL COMPANY 


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11 "—10.7 lbs. I Joist 




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THE NATIONAL PRESSED STEEL COMPANY 


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10"—9.5 lb. I Joist 


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THE NATIONAL PRESSED STEEL COMPANY 


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10"— 8.7 lb. I Joist 


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THE NATIONAL PRESSED STEEL COMPANY 


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9"—7.7 lb. I Joist 


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THE NATIONAL PEESSED STEEL COMPANY 


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THE NATIONAL PRESSED STEEL COMPANY 


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THE NATIONAL PRESSED STEEL COMPANY 


Steel Lumber Accessories 




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STEEL LATH 


21 






























































































--- 1 

THE NATIONAL PRESSED STEEL COMPANY 


DESIGNING DATA 

In designing Steel Lumber floor construction, the 
strength of the Steel Joists only is taken into account. 
The type of floor or ceiling finish has no bearing on the 
carrying capacity except as concerns the requirements of 
the span between joists. 

Because of the method of production, which gives the 
steel extra heating and working, a refined and more com¬ 
pact fibre is secured, resulting in an ultimate strength of 
72,000 lbs. per sq. inch with a high elastic limit. A fibre 
stress of 16,000 lbs. per sq. inch is used in all calculations 
in this handbook, which gives a high factor of safety. 
Repeated loading tests under official direction in various 
parts of the country have shown that a finished floor con¬ 
struction will carry approximately three times the designed 
live load before deflecting as much as 1/360 of the span. 

When supported on masonry walls the joists should 
have a bearing equal to one half their depth and not less 
than 4 inches. When supported on steel sections they 
should have a bearing not less than two inches. Joists 
should never be riveted to steel supporting members 
except where some special framing detail is required. 

Reference to the cost curve, page 67, will indicate the 
more economical spans for any loading condition. These 
curves should be studied in designing panel sizes with the 
object of effecting the greatest economy consistent with 
architectural requirements. 

Economy in building construction calls for that design 
which develops the requisite strength and measure of 
durability without waste of materials. Live load require¬ 
ments should be consistent with the proposed occupancy 
and uniform dependability of structural materials to be 
used. Designed floor slab spans have a decided effect on 
building costs. Certain architectural features sometimes 
develop a structural cost exceeding any possible worth. 
Necessarily each project offers individual problems which 
demand careful study to insure efficient economy. 

Structural designing involves careful comparison and 
analysis. The finished result should represent a balanced 
condition of all the structural parts. In this handbook 
an effort has been made to present such information as will 
enable the designer to lay out the structural features with 
the greatest resulting economy consistent with the archi¬ 
tectural requirements. 


22 




THE NATIONAL PRESSED STEEL COMPANY 


Safe Loading Tables 

EXPLANATORY NOTES 

The National Steel Joist is a light weight member 
produced by an entirely different method and performs 
a different function than Rolled Structural Sections. All 
safe loading tables assume the steel joists to be braced 
laterally. This bracing being automatically taken care of 
in either the floor or partition construction by steel bridg¬ 
ing, steel lath and concrete as called for in the specifications. 

The method of production and the carbon content of 
material produces a steel with ultimate strength running 
uniformly over 70,000 lbs. per square inch with elastic 
limit uniformly over 60,000 lbs. per square inch. In all 
safe loading computations a fibre stress of 16,000 lbs. per 
inch has been used, thus giving a safety factor against the 
elastic limit of practically 4. In cases where code regula¬ 
tions permit, a fibre stress of 20,000 lbs. per sq. inch is 
amply safe giving due consideration to deflection limits. 

To accommodate the 96-inch length of steel lath 
sheets four common spacings of steel joists have been 
developed as standard—12", 16", 19" and 24". The spring 
lath clip makes firm attachment at the end of the lath 
sheet and practically no lath is lost in end laps. The proper 
spacing of joists to be used is largely a matter of economical 
design, bearing in mind the use to which the floor is 
intended. Because of the concentrated loads which may 
be applied a garage floor should have the joists spaced as 
a rule not more than 16" c-c, while a school house or office 
building floor can be economically and safely constructed 
with joists 24" c-c. Wherever heavy concentrated loads 
may be applied it is advisable to check into the strength 
of the floor slab between joists (Table page 129). 

Properties of Sections. —The properties given are 
calculated from the exact dimensions as shown on pages 
24 to 33 inclusive. These properties being the basis of all 
computations for safe loadings. 


23 





THE NATIONAL PRESSED STEEL COMPANY 


Safe Loading Tables. —A Fibre stress of 16,000 lbs. 
per sq. inch has been used throughout except where cor¬ 
rection is made for deflection, page 163, and fora Moment = 
WL/8. For continuous beam running over supporting 
girders use corrected loadings as per formulae given (page 
158). In all cases the loads shown include dead and live 
load. For dead load of floor see page 130. 


Total Uniformly Distributed Loads. —This table 
shows the total uniformly distributed loads. Heavy lines 
show theoretical deflection limit of 1/360 of the span 
(page 26). 


Total Uniformly Distributed Loads Corrected for 
Deflection. —None of the loads shown on this table will 
give a deflection exceeding 1/360 of the span (page 27). 

Total Uniformly Distributed Loads per Square 
Foot of Floor Area. —For convenience in designing these 
square foot floor load tables have been developed for the 
four standard joist spacings. All of the loads shown will 
give a deflection less than 1/360 of the span (pages 28-31). 

Safe Partition Loads. —Where steel studs are used 
in partition construction with lath and plaster on both 
sides, the carrying capacity of the studs is based on the 
long radius of gyration (page 32). 

Safe Strut Loads. —Where Steel Lumber Sections 
are used as struts without lath and plaster, safe loads are 
based on the short radius of gyration (page 32). 

Web Crippling Values. —Safe loads uniformly dis¬ 
tributed on the spans given in loading tables will not 
produce average shearing stresses in the web greater than 
10,000 lbs. per sq. inch. In order to check web values for 
unusual conditions, information has been developed as 
shown in table (page 33). 


24 






PROPERTIES OF NATIONAL STEEL I JOISTS 


THE NATIONAL PRESSED STEEL COMPANY 



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^ *h Ov t"» O O CN ro 
iO rf *—I'^vOO'OOaO 

CN'^^’HN'^COOOO'O 
th h cn ro ro >0 O 

CO 

<v 

tC 

a 

E 

a 

Inches 

lO 10 10 »o 10 

OONN(NrS(NlOlO>0 

I^IOIO'OO'O'ONNN 

‘o 

-u 

U 

£ 

o 

Inches 

oooooooooo 

OOOlOOO©LO»OLO 

Thicknessof MetalJ 

tti 

Inches 

t^vOOOCN'©H , H | CNH h H i 

■^■^^ioiovO^OOOnO 

t-H t-H t-H t-H t-H t-H t-H t-H t-H CN 

w 

Inches 

CSfO'^vOOOCNI^TH^CN 

r^r^r^t^-t^ooooO\©0 

OOOOOOOO©^ 

Area of 
Section 

Sq. In. 

OO^CV)OnOO'^ i '^OnvOC v I 

O CN Tj< O 0> CS ^ N HU) 

rtT-IHrlHCNtSKSfOCO 

Weight 

per Ft. 

Pounds 

t^r00N00 00Nt^u)NO 

f0 , ^' ! t 1 O'Ot^000NOCS 

t-H t-H 

Depth 

Q 

Inches 

— 



Moment of Inertia S = Section Modulus R = Radius of Gyration 









































































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STEEL I JOISTS 


Total Safe Loads in Pounds Uniformly Distributed. 
Loads Given Include Weight of Construction. v 
Fibre Stress Not Exceeding 16,000 Lbs. per Square Inch. 


Size 

4" 

5" 

6" 

7" 

8" 

9" 

10' 

10" 

li" 

12" 

Weight 

3.7 

4.3 

4.9 

5.8 

6.8 

7.7 

8.7 

9.5 

10.7 

12.0 


6' 

2285 

3158 

4216 









7' 

1958 

2707 

3614 









8' 

1713 

2368 

3162 

4375 








9' 

1523 

2105 

2811 

3888 

5244 

6466 






10' 

1371 

1895 

2530 

3500 

4720 

5820 

7170 

8120 

9880 

11720 


11' 

1248 

1721 

2300 

3180 

4290 

5290 

6520 

7380 

8980 

10680 


12' 

1142 

1579 

2107 

2918 

3930 

4850 

5975 

6770 

8230 

9790 

<u 

<L> 

13' 

1055 

1458 

1945 

2690 

3630 

4480 

5520 

6250 

7600 

9040 


14' 

980 

1354 

1805 

2500 

3370 

4160 

5120 

5800 

7060 

8390 


15' 


1262 

1688 

2330 

3145 

3880 

4780 

5420 

6580 

7830 

a i 

a. 

16' 

.... 

1185 

1580 

2185 

2950 

3640 

4480 

5080 

6170 

7340 

CO 

17' 


1115 

1489 

2060 

2787 

3422 

4220 

4780 

5810 

6910 

aj 

<D 

18' 

.... 

1052 

1405 

1943 

2620 

3235 

3985 

4520 

5480 

6520 

u 

19' 



1332 

1842 

2482 

3064 

3770 

4280 

5200 

6180 


20' 



1265 

1750 

2360 

2910 

3585 

4060 

4940 

5860 


21' 


. 

1665 

2248 

2770 

3410 

3870 

4700 

5590 


22' 




1590 

2142 

2645 

3260 

3690 

4480 

5340 


23' 




4290 

5110 


24' 









4115 

4890 


25' 









3950 

4690 


26' 









3800 

4520 












Note —For loads below horizontal lines, deflection 
is theoretically greater than the allowable limit for plas¬ 
tered ceilings (1/360 of the span). 

The above safe loads assume that the joists are braced 
laterally as in the standard floor construction. 


26 
































































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STEEL I JOISTS 

Total Safe Loads in Pounds Uniformly Distributed. 
Loads Given Include Weight of Floor Construction. 
Fibre Stress Not Exceeding 16,000 Lbs. per Square Inch. 

No Deflections Greater Than 1/360 of the Span 
Produced by the Given Safe Loads. 


Size 

4" 

5" 

6" 

7" 

8" 

9" 

10" 

10" 

li" 

12" 

Weight 

3.7 

4.3 

4.9 

5.8 

6.8 

7.7 

8.7 

9.5 

10.7 

12.0 


6' 

2285 

3158 

4216 









7' 

1958 

2707 

3614 









8' 

1713 

2368 

3162 

4375 








9' 

1364 

2105 

2811 

3888 

5244 

6466 






10' 

1103 

1895 

2530 

3500 

4720 

5820 

7170 

8120 

9880 

11720 


11' 

913 

1575 

2300 

3180 

4290 

5290 

6520 

7380 

8980 

10580 

4— > 

<D 

12' 

768 

1323 

2107 

2918 

3930 

4850 

5975 

6770 

8230 

9790 

OJ 

Uh 

13' 

• • • • 

1128 

1805 

2690 

3630 

4480 

5520 

6250 

7600 

9040 

_c 

14' 


973 

1558 

2500 

3370 

4160 

5120 

5800 

7060 

8390 

c 

15' 



1358 

2190 

3145 

3880 

4780 

5420 

6580 

7830 

d 

o 

16' 



1192 

1925 

2950 

3640 

4480 

5080 

6170 

7340 

c ri 

17' 




1705 

2625 

3422 

4220 

4780 

5810 

6910 

U 

a 

18' 




1520 

2340 

3235 

3985 

4520 

5480 

6520 

<V 

r \ 

19' 





2100 

2918 

3770 

4280 

5200 

6180 


20' 





1895 

2638’ 

3585 

4060 

4940 

5860 


21' 






2395 

3280 

3720 

4700 

5590 


22' 






2178 

2990 

3390 

4480 

5340 


23' 








3100 

4130 

5110 


24' 








2840 

3790 

4890 


25' 








2620 

3500 

4530 


26' 








2420 

3230 

4190 













Note—T he above safe loads assume that the joists are 
braced laterally as in the standard floor construction. 


27 




























































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STEEL I JOISTS 


Total Safe Loads in Pounds per Square Foot of Floor Area. 
Loads Given Include Weight of Floor Construction. 

\ 

Fibre Stress Not Exceeding 16,000 Lbs. per Square Inch. 

_ No Deflections Greater Than 1/360 of the Span 

Produced by the Given Safe Loads. 

Joist Spaced 12" on Centers 


Size 

4" 

5" 

6" 

7" 

8" 

9" 

10' 

Weight 

3.7 

4.3 

4.9 

5.8 

6.8 

7.7 

8.7 


6' 

381 

527 

703 






r 

280 

387 

516 






8' 

214 

296 

395 

S47 





9' 

152 

234 

312 

432 

583 

718 

885 


10' 

110 

190 

253 

350 

472 

582 

717 


IP 

83 

144 

209 

289 

390 

481 

593 

-M 

12' 

64 

110 

176 

243 

328 

404 

498 

<V 

fr 

13' 

.... 

87 

139 

207 

279 

345 

425 

C 

14' 


70 

111 

179 

241 

297 

366 


15' 



91 

146 

210 

258 

318 

e 

rfl 

16' 



75 

120 

184 

228 

280 

Cl 

r/l 

17' 




100 

154 

202 

248 

u 

18' 



i 

84 

130 

180 

222 

<v 

19' 





110 

153 

198 

U 

20' 





95 

132 

179 


21' 






114 

156 


22' 






99 

136 


23' 









24' 









25' 









26' 









10 " 


9.5 


482 

414’ 

361 

318 

281 

251 

225 

203 

177 

154 

135 

118 

105 

93 


li" 


10.7 


585 

504 

438 

386 

342 

304 

274 

247 

224 

204 

179 

158 

140 

124 


12 " 


12.0 


695 

598 

522 

458 

406 

362 

325 

293 

266 

242 

222 

204 

181 

161 


Note —The above safe loads assume that the joists are 
braced laterally as in the standard floor construction . 


28 





























































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STEEL I JOISTS 

Total Safe Loads in Pounds per Square Foot of Floor Area. 

Loads Given Include Weight of Floor Construction. 

Fibre Stress Not Exceeding 16,000 Lbs. per Square Inch. 

No Deflections Greater Than 1/360 of the Span 
Produced by the Given Safe Loads. 

Joists Spaced 16" on Centers 


12 " 


12.0 


521 

448 

392 

344 

305 

272 

244 

220 

200 

182 

167 

153 

136 

121 


Note —The above safe loads assume that the joists are 
braced laterally as in the standard floor construction. 


Size 

4" 

5" 

6" 

7" 

8" 

9" 

10" 

10" 

li" 

Weight 

3.7 

4.3 

4.9 

5.8 

6.8 

7.7 

8.7 

9.5 

10.7 


6' 

286 

395 

526 








V 

210 

290 

387 








8' 

161 

222 

297 

410 







9' 

114 

176 

234 

324 







10' 

83 

142 

190 

263 

354 

437 

538 

608 



IP 

62 

108 

157 

217 

292 

361 

445 

503 


4 -> 

0) 

12' 

48 

83 

132 

183 

246 

303 

374 

423 


0) 

13' 


65 

104 

155 

210 

259 

319 

361 

438 

G 

14' 


52 

84 

134 

181 

223 

275 

311 

378 


15' 



68 

110 

158 

194 

239 

271 

328 

G 

flj 

16' 



56 

90 

138 

171 

210 

238 

289 

a 

in 

17' 




75 

116 

151 

186 

211 

257 

U 

18' 




63 

98 

135 

166 

188 

228 

a 

19' 





83 

115 

149 

169 

205 

u 

20' 





71 

99 

135 

152 

185 


21' 






85 

117 

133 

168 


22' 






74 

102 

116 

153 


23' 








101 

135 


24' 








89 

118 


25' 








79 

105 


26' 








70 

93 


29 


































































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STEEL I JOISTS 

Total Safe Loads in Pounds per Square Foot of Floor Area. 
Loads Given Include Weight of Floor Construction. 

Fibre Stress Not Exceeding 16,000 Lbs. per Square Inch. 
No Deflections Greater Than 1/360 of the Span 
Produced by the Given Loads. 

Joist Spaced 19" on Centers 


Size 


Weight 



6' 


V 


8' 


9' 


10' 


11' 

4—> 

12' 

<t> 

0J 

13' 

U- 

14' 

.2 

15' 

c 

oj 

a 

16' 

17' 

cn 

u 

18' 

a; 

19' 

U 

20' 


21' 


22' 


23' 


24' 


25' 


26' 


4" 

5" 

6" 

7" 

8" 

9" 

10' 

10" 

li" 

12" 

3.7 

4.3 

4.9 

5.8 

6.8 

7.7 

8.7 

9.5 

10.7 

12.0 

241 

177 

135 

96 

70 

53 

41 

332 

244 

187 

148 

120 

90 

70 

55 

44 

443 

326 

250 

197 

160 

132 

111 

88 

70 

57 

47 















346 

273 

222 

183 

153 

131 

113 

92 

76 

63 

53 













298 

247 

207 

176 

152 

132 

116 

98 

82 

70 

60 

368 

304 

256 

218 

188 

163 

144 

127 

114 

97 

83 

72 

62 

452 

375 

315 

269 

231 

201 

177 

157 

140 

126 

113 

99 

86 

513 

423 

356 

304 

262 

228 

200 

177 

159 

142 

128 

112 

97 

85 

75 

66 

59 







369 

318 

277 

244 

216 

192 

173 

156 

141 

129 

114 

100 

88 

78 

439 

378 

329 

290 

257 

229 

206 

185 

168 

153 

140 

129 

114 

102 


























































Note —The above safe loads assume that the joists are 
braced laterally as in the standard floor construction. 


30 






























































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STEEL I JOISTS 

Total Safe Loads in Pounds per Square Foot of Floor Area. 
Loads Given Include Weight of Floor Construction. 

Fibre Stress Not Exceeding 16,000 Lbs. per Square Inch. 

No Deflections Greater Than 1/360 of the Span 
Produced by the Given Loads. 

Joists Spaced 24" on Centers 


<u 

4 > 

Uh 


c 

a 

a. 

m 

!_ 

<v 

U 


ize 

4" 

5" 

6" 

7" 

8" 

9" 

10' 

10" 

li" 

12" 

ight 

3.7 

4.3 

4.9 

5.8 

6.8 

7.7 

8.7 

9.5 

10.7 

12.0 

6' 

191 

264 

351 








7' 

140 

194 

258 








8' 

107 

148 

198 

274 







9' 

76 

117 

156 

216 

292 

359 





10' 

55 

95 

127 

175 

236 

291 

359 

406 



ii' 

42 

72 

105 

145 

195 

240 

296 

335 



12' 

32 

55 

88 

122 

164 

202 

249 

282 



13' 


43 

70 

104 

140 

172 

212 

240 

292 

348 

14' 


35 

56 

89 

120 

149 

183 

207 

252 

299 

15' 



45 

73 

105 

129 

159 

180 

219 

261 

16' 



37 

60 

92 

114 

140 

159 

193 

229 

17' 




50 

77 

100 

124 

140 

171 

203 

18' 




42 

65 

90 

111 

125 

152 

181 

19' 





55 

77 

99 

113 

137 

162 

20' 





47 

66 

90 

101 

123 

146 

21' 






57 

78 

89 

112 

133 

22' 






49 

68 

77 

102 

121 

23' 








67 

90 

111 

24' 








59 

79 

102 

25' 








52 

70 

91 

26' 








47 

62 

81 


Note—T he above safe loads assume that the joists are 
braced, laterally as in the standard floor construction. 


31 




























































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STEEL PARTITION STUDS 


Total Safe Load in Pounds for Each Stud. Using Column 
Formula for Fibre Stress. 


(/-19000 lb.-^r) with Max. of 13000 lb. per Sq. Inch 


R, About Axis A-A is for Studs 
Plastered both sides. 

R, About Axis B-B is for Un¬ 
plastered Studs. 



B 


A 


B 


Axis A-A Plastered Both Sides 


Axis B-B Unsupported Studs 


Size 

4" C 

4" I 

4" C 

4" I 

Size 

Weight 

1.85 

3.7 

1.85 

3.7 

Weight 


2 



6980 

13975 

2 

• 


3 



6680 

13975 

3 



4 



5500 

13200 

4 



5 



4320 

11420 

5 



6 

6988 

13975 

3140 

9640 

6 


4-i 

0) 

0) 

7 

6988 

13975 

1980 

7840 

7 

a; 

0> 


8 

6864 

13728 

806 

5988 

8 


G 
• ^ 

9 

6425 

12850 


4200 

9 


4 -> 

JG 

10 

6025 

12050 


2370 

10 

4-> 

,b|0 

11 

5600 

11200 



11 

_bf 

IT! 

12 

5180 

10360 



12 

<D 

T. 

v_ 

13 

4775 

9550 



13 

u 

a 

<D 

14 

4360 

• 8720 



14 

a 

u 

15 

3925 

7850 



15 

U 


16 

3510 

7020 



16 



17 

3090 

6180 



17 



18 

2685 

5370 



18 



19 

2260 

4520 



19 



20 

1830 

3660 



20 







Safe load values above horizontal lines are for ratios 
of 1/r not over 120. 

No loads given for ratios of 1/r greater than 200. 


32 









































































THE NATIONAL PEESSED STEEL COMPANY 


Web Resistance Values 


d 

t 

V 

R 


Depth 

of 

Joist 

Weight 

Per 

Foot 

Single 
Thickness 
of Web 

Allowa ble 
Web 
Shear 

Allowable 

Buckling 

Resistance 

Results 
of Test 
(Average) 

Inches 

Pounds 

Inches 

Pounds 

Pounds 

Pounds 

4 

3.7 

.072 

5.760 

3410 

8760 

r 

5 

4.3 

.073 

7300 

3420 

7470 

6 

4.9 

.074 

8880 

3340 

7660 

7 

i 

5.8 

076 

10640 

3330 

6340 

8 

6.8 

.078 

12480 

3320 

6620 

9 

7.7 

.082 

14760 

3540 

7380 

10 

8.7 

.087 

17400 

3860 

7750 

10 

9.5 

.091 

18200 

4350 

8630 

11 

10.7 

.097 

21340 

4840 

9370 

12 

12.0 

.102 

24480 

5230 

9970 


Example explaining method of computation shown on page 34. 


33 































THE NATIONAL PRESSED STEEL COMPANY 


WEB RESISTANCE 

The web of a steel joist differs from the web of a struc¬ 
tural section in that it is composed of two pieces. The 
question naturally rises as to whether the two parts of 
the web will act together and give the same results as 
one piece of the same total thickness. Theoretical analysis 
of the web acting as a beam indicates, and loading tests 
prove, that in the consideration of bending moments and 
horizontal shear the results are the same as in a one piece 
web. The reverse is true, however, in resistance to 
buckling. 

One column in table, page 33 shows the results of tests 
to the elastic limit. This series of tests were run on sec¬ 
tions four feet l^ng. Each sample was supported at each 
end and the load applied at one end of the joist. This con¬ 
dition exactly duplicated the loading which would be 
applied on the joists by a bearing partition and developed 
the web resistance to direct crushing load. The figures 
given are for the elastic limit which was always evidenced 
by the dropping of the machine scale arm when that point 
was reached. 


Each result given represents the average of six test 
pieces. The samples were cut with the spot welds at 
various distance from the end. The location of the spot 
weld made no difference in the results, all the figures 
running very uniform. 

Theoretical analysis indicates that in this regard the 
web of a steel joist should be considered as two separate 
sections. It is true that the welds hold the channel webs 
together and that they work in unison, but for ample 
safety in design we recommend they be considered as 
operating independently. 

With the above in mind and wishing to determine the 
total shear in pounds due to end reaction, the following 
formula is developed. 

d—total depth of joists 
t—thickness of strip 


Taking Cambria formula for total shear 
due to end reaction 


12000 dt 


1 + 3000 t2 

As there are no fillets at the angle of flange and web in 


the steel joist, the total depth of joist is used. d = 


c. 


34 





THE NATIONAL PRESSED STEEL COMPANY 


The web is considered as two columns each with a 
thickness of (t) 

Then 

Total Resistance to Buckling 


2 x12000dt 

R =- 

d 2 

1 -)- 

3000 t 2 


24000 dt 


d 2 

1 d- 

3000 t 2 


The results for safe buckling due to end action in 
table, page 33 are computed on this formula. 

It is interesting to note that in the test above mentioned 
all the samples when submitted at a later date, to a 
second, identical test loading, developed from seventy-five 
to eighty per cent of their original strength. 

All tables of safe loads for National Steel Joist sections 
are calculated on the assumption that proper provision 
is made to prevent lateral deflection and turning of the 
sections. 

Such condition is provided in the standard floor con¬ 
struction where the joists will in every instance exceed the 
loading values given. 


35 








THE NATIONAL PRESSED STEEL COMPANY 



BEAM CLIPS 


Where steel joists rest directly on top of rolled steel 
beams it is advisable that joist be held in place by a clip 
as illustrated above. 

The clip serves to securely anchor the joist to the beam, 
to preserve correct spacing and otherwise prevent all 
movement of joists during installation. 

In roof construction, in floors over basement, or 
wherever projection of beams is permissible, joists should 
rest on the top flange, thereby eliminating the cost of 
shelf angles and fabricating expense on beams. 

The same clip may be used to secure joists to top 
chord of roof trusses and to flange of riveted girders. 

Clips are quickly attached to beams by the simple 
operation of bending ends of rods down and under the 
beam flange. 

Table on next page gives proper size of clip required 
for different Rolled Steel beams. 

Beam Clips are made from No. 14 Ga. (.083"), black 
strip steel. 


36 




























































THE NATIONAL PRESSED STEEL COMPANY 




for 

P'S" 6" & 7" Steel I Joist 


\"— 4 1—*j 
J lk- • 



CLIP “B” for 
8" 9" 10" 11" & 12" 
Steel I Joist 


Beam Clips for Various Sizes Steel I Joists 
and Structural Steel Beams 


Beam Clip 
Designation Mark 

Length 

of 

Rods 

Structural Steel Beams 

Weight 

per 

100 

Pieces A 

i 

Weight 

per 

100 

Pieces B 

Standard 

Bethlehem 

A 

B 

9" 

10"—I 
12"—I 
15"—I 

8"—I 
9"—I 

80 

90 

A 

B 

10" 

18"—I 
20"—I 

10"—I 
12"—I 

80 

90 

A 

B 

11" 

42"—I 

15"—I 

80 

90 

A 

B 

12" 


18"—I 
20"—I 

85 

95 

A 

B 

13" 


24"—I 

85 

95 

A 

B 

14" 


26"—I 
28"—I 

85 

95 


When ordering beam clips give A or B designation 
mark, also length of rods as “A—9” or “B—9.” 


37 
































































































THE NATIONAL PRESSED STEEL COMPANY 



BEAM FURRING CLIPS 

To properly fireproof rolled steel beams, the steel lath 
should be furred away so as to secure an air space between 
plaster and beam. This is accomplished by the use of 
beam furring clips illustrated above which are securely 
fastened to the I beam by bending leg of clip over the 
beam flanges. 

Three-quarter inch channels are supported on the seat 
of clip and held in a manner to prevent contact of fire¬ 
proofing with beam and also to insure a true form for 
beam and straight edge for application of lath and plaster. 

Clips should be spaced not to exceed 30" centers along 
the beams. 

Table on next page shows size of clip required for various 
Rolled Steel Beams. 

Beam Furring Clips are made from No. 15 Gauge 
(.072") black strip steel. 


38 



































THE NATIONAL PRESSED STEEL COMPANY 



Beam Furring Clip for Various Sizes of 
Structural Steel Beams 


Designa¬ 

tion 

Mark 

Dimen- 

Structural Steel Beams 

Weight 

A 

Standard 

Bethlehem 

per 

100 pcs. 

F—3 

3 " 

4"—1@ 10.5 
5"—1@ 10.0 


50 

F-3V 2 

3/4 " 

5"—1@ 14.75 
6"— 1@ 14.75 


53 

F—4 

4 " 

7"—1@ 20.0 
8"—1@ 18.4 


57 

F—434 

4 34 " 

9"—1@ 21.8 


60 

F—5 

5 " 

10"— 1@ 25.4 
12" I@ 31.8 


63 

F— sy 2 

5^" 

1-2"—I @ 40 
15"—1@ 42.9 

8"—1@ 17.5 
9"—1@ 20 

67 

F—6 

6 " 

15"—1@ 60 
18"—1@ 54.7 

10"—I @ 23.5 

70 

F—634 

634 " 

20"—1@ 65.4 

12"—1@ 28.5 
12"—I @ 36 

73 

F—7 

1 

20"—I @ 80 
24"—I @ 80 

15"—1@ 38 
15"—1@ 54 

76 

i 

oo 

8 " 

24"—I @ 105 

20"—1@ 59 

83 

F—9 

9 " 

24"—1@ 74 
27"—1@ 90 

20"—I @ 72 
24"—1@ 73 

89 

F—10 

10 " 


28"— 1@ 105 

96 


When ordering Beam Furring Clips give designation 
mark as “F—7.” 


39 



































































































THE NATIONAL PRESSED STEEL COMPANY 


STEEL LATH 

There are many types of Steel Lath made in various 
gauges, and each type possessing distinctive merit for 
some specific purpose. Few of the various types are 
particularly well qualified, however, for use with Steel 
Lumber. When choosing a lath for that purpose the 
following points should be considered: 

Rigidity Size of sheet 

Area of openings Gauge and weight 

Key Ease of handling 

Plastering surface Adaptability 

In considering the rigidity of a lath the joist spacing 
on the job in question is a deciding factor. As any instal¬ 
lation is apt to use at some point a 24" joist spacing it is 
well to pick a lath adapted for that condition. Certainty 
of satisfaction on the closer centering is then assured. 
The term rigidity means supporting strength. The 
measure of rigidity of a lath is the amount of deflection 
under load or pressure. 

To visualize the importance of rigidity examine a 
normal condition resulting from the use of many types 
of lath. Assume joist spacing 24" and a lath deflection of 
2 L 2 " at the center under application of 2" of wet concrete. 
This loss of concrete means an added thickness averaging 
1 inch for every square foot of floor area. The cost of 
this concrete waste at least equals the cost of the lath. 
The use of a cheap lath should always be guarded against 
as the resulting loss in concrete will amount to many 
times the saving in the cost of lath. 

When applied to ceilings there is nothing so detri¬ 
mental to good rapid plastering as a lath that “springs,” 
deflects under pressure of the trowel. On the other hand, 
a good, rigid steel lath with a mesh design which holds 
fresh plaster is the best plastering surface obtainable. 

The best results in connection with Steel Lumber on 
all spacings will always be secured by using a Ribbed 
Lath. The same lath should always be used on both 
floors and ceilings. They are equally important. 

The area of the mesh openings affects the amount of 
plaster used and if too large, will permit floor slab con¬ 
crete to run through the mesh. The area of opening is 
controlled by the percentage of expansion, the width of 
strands and the position of the strands. In some laths 


40 




THE NATIONAL PRESSED STEEL COMPANY 


where the opening area is very large the expansion has 
been carried to the point where the strand metal is past 
the elastic limit. Any further stress applied in handling 
or installing will break many strands. The width of 
strands is important for the reason that a narrow cut strand 
will not hold fresh plaster, neither does it have the lateral 
stiffness so important to the lather in handling. The 
position of the strand refers to whether it lies vertical or 
horizontal. If the strand presents a cutting edge to the 
plaster it decreases the necessary pressure of applying. 
Neither a vertical or horizontal strand gives best results 
in this regard. The horizontal strand gives the strongest 
key and better holds fresh plaster. The most efficient 
position is slightly tilted from horizontal thus presenting 
cutting edge to plasterer and at the same time retaining 
the fresh plaster. 

The shape of the mesh is important. Long rectangular 
meshes being very wasteful. Experience has proven that 
the. most practical and serviceable mesh is the so-called 
“Diamond” design, with clear dimensions not exceeding 
IX" by 

If in installation the lather can place a wider sheet of 
one lath in the same time that he would place a narrow 
sheet of another, the results are lower lathing costs. Also 
the loss on side laps and time in lap wiring is decreased. 
The lateral stiffness of a lath determines the width of 
sheet that can be efficiently handled. Lateral stiffness 
being dependent on the mesh design and gauge of metal. 
A lath easily handled in a 24" by 96" sheet is the most 
practical. 

What is called the body of the lath is directly dependent 
on its gauge. Gauge also is the important factor for 
durability under every circumstance. The weight of lath 
determines the strand width for any particular design 
and gauge. In connection with Steel Lumber a 24 gauge 
ribbed Diamond mesh lath weighing 4 lbs. to the sq. 
yd. will always give good service. In many places for 16" 
joist spacing the same lath, made of 26 gauge steel 
and, weighing 3 lbs. to the sciuare yard, is ample. 

If a lath is so designed as to be easy no handle, with 
no ragged, sharp, cutting edges in the mesh it will be 
erected more economically and satisfactorily. If the 
same design, weight and gauge of lath will economically 
meet every condition of loading and spacing of supports, 
the erection problem is greatly simplified. A lath easily 


41 







THE NATIONAL PRESSED STEEL COMPANY 


installed and universally adapted to all joist spacings, 
whether used in floors, ceilings or walls, functioning with 
a minimum of deflection, and giving the greatest rein¬ 
forcing value to both plaster and floor slab concrete, is 
the best in combination with Steel Lumber. 

We recommend the universal use of 24 gauge ribbed, 
Diamond mesh lath, weighing not less than 4 pounds 
to the sq. yard. For mesh and other general dimensions 
refer to page 21. A number of good laths will serve the 
purpose equally well but the adopting of this design as 
a comparative standard will result in good material 
and greater satisfaction with Steel Lumber construction. 
On 16" spacing under most conditions, the same design 
of lath in 26 gauge, weighing 3 pounds to the square 
yard, is satisfactory. 


METHOD OF APPLYING RIBBED DIAMOND 
MESH STEEL LATH 

Floors: 

Lath should be applied with ribs up, the sheets running 
at right angles to direction of joists and fastened by 
means of spring clips illustrated on page 47. The lath 
should be secured every 12 inches, that is three clips be 
used across the lath at each joist, one clip at center of 
sheet and one clip at each side. Side lap should be made 
by nesting the outside rib of lath. This provides an 
effective covering width of 24 inches for each sheet. The 
lap at ends of sheet should occur over the center of joists. 
By springing clips over the ribs greater rigidity is secured. 

Ceilings: 

Ceiling lath should be applied with ribs up and secured 
to the joists by means of spring clips illustrated on page 
45. End and side laps should be accomplished in same 
manner as described above for floor lath. Care should 
be taken to wire the edges of the two sheets midway 
between the joists so that the sheets cannot separate 
when plaster is applied. At the junction of ceiling and 
wall it is good practice to run ceiling lath down wall a 
distance of 6 inches, this for the purpose of reinforcing 
plaster at that point and preventing cracks. 


42 




THE NATIONAL PRESSED STEEL COMPANY 


Partitions: 

Steel lath is secured to Steel Lumber Channel Studs 
by wiring through holes punched in flanges for that 
purpose. This punching of the Channel Studs is usually 
done in the field by a hand punch, sometimes at 
fabricating plant, depending on arrangements made. 
(Punching never done at the mill.) Lath should be 
carefully attached at edges and at intervals of 6 inches 
along the studs. The ends of sheets on partition construc¬ 
tion should be staggered alternately to provide additional 
lateral bracing for the studs during erection. 

Where plain channels, angles or other forms of sup¬ 
ports are provided either in partition construction or in 
beam or column furring, steel lath is tied to the support 
with No. 18 gauge, galvanized tie wire, at intervals of 
approximately 6 inches or as required to provide a firm 
and rigid surface to receive the plaster. 

General: 

The standard spacing as established for joists, pub¬ 
lished elsewhere in handbook, provides for the economical 
use of a standard 96" sheet of Steel Lath without waste. 
When supports are spaced not to exceed 24-inch centers 
a 24 gauge ribbed Diamond mesh lath, weighing not less 
than 4 lbs. per square yard, is sufficiently rigid to support 
a concrete slab or plaster ceiling without intermediate 
support or centering. 

Note: 

When joist spacing is such that the ends of the lath 
sheets butt at centre of joist without lapping, the spring 
lath clip holds the lath rigidly. When lath is being nailed 
to the joist then each lath sheet must cover the center of 
joist. The spring lath clip in this way saves waste of lath 
at end laps. Page 47. 


43 




THE NATIONAL PRESSED STEEL COMPANY 


SPRING CLIPS 

The adoption of Spring Clips for fastening steel lath 
to Steel Joists has been an important development in 
Steel Lumber Construction, The old-fashioned prongs 
or the regularly spaced holes punched from the joist 
flange, both of which reduce the strength of the section 
and add to manufacturing costs, are eliminated. The top 
and bottom flanges, therefore, are identical and being 
symmetrical the joists can be handled with greater 
facility and more quickly erected without regard for top 
or bottom side. 

Spring Clips are made from highest grade spring steel, 
heat treated and oil tempered to provide proper degree of 
toughness and strength. The clips are so shaped as to 
fit the joist flange, the convex center pressing upon the 
flange provides the elasticity which firmly holds the lath 
to the joist after clip is sprung into place. As the clip is 
supported at the outer edge of the joist it extends 
entirely across the flange, thereby giving the widest 
possible support for the lath as well as reducing to a 
minimum the net span of the lath. 



Clips Sprung Over Ribs 


44 








































THE NATIONAL PRESSED STEEL COMPANY 


Applying Spring Lath Clips 

A diamond mesh rib lath as described on pages 40 to 
42 is recommended for universal use in connection with 
Steel Lumber. This lath lends itself to the use of spring 
clips as the clips can be applied over the ribs, thereby 
providing a much firmer fastening for the lath, also the 
clips can be more easily and quickly inserted through the 
diamond shaped meshes than is possible with other types 
of lath. 



The method of attaching the clip is extremely simple. 
One end of the clip is passed through the mesh of the 
lath and hooked over the small vertical flange of the 
joist. With the clip in this position pass the other end 
through the lath in like manner. Tap the free end of 
clip lightly with a hammer, forcing the angle end of clip 
to extend through lath and hook itself over vertical joist 
flange. 

The spring clip fits snugly up against the lath and is so 
designed as to equalize any differences in length of the 
secondary flanges on the steel joists. 


M 


45 





















THE NATIONAL PEESSED STEEL COMPANY 


Spring Lath Clips Used on Ceilings 



Lath in Position on Ceiling 

For fastening ceiling lath to lower flange of joist, 
clips are applied in manner as described before. They 
should be spaced on 8-inch centers or over every other • 
rib (when ribs are spaced 4 inches center to center). 
Where lath sheets lap at sides the clip should be applied 
over both ribs after they are nested. This practice results 
in more economical use of clips, at same time provides 
more rigidity in the lath and a smoother ceiling for the 
application of plaster. 

When joists are spaced 24 inches on centers it is advis¬ 
able to wire the edges of the two sheets midway between 

the joists so that sheets cannot separate when plaster is 
applied. 


46 





























































THE NATIONAL PRESSED STEEL COMPANY 


Spring Lath Clips Used on Floors 



The use of spring clips on floors is recommended in 
preference to the older method of nailing into web of 
joist. The clip is more easily and rapidly applied and 
decidedly more effective in making a secure fastening for 
the lath. Clips spaced 12 inches on centers along joists 
or three clips for each 24-inch sheet of lath will securely 
hold the lath in place. One clip should be applied over 
center rib and one cliD over rib at side where lap is made 
by nesting the ribs of adjoining sheets. The clip holding 
the middle of sheet should alternate on different ribs and 
where end of lath sheet butts or laps over joist it is advis¬ 
able to use two clips instead of one to fasten middle of 
sheet. 



47 












































































THE NATIONAL PRESSED STEEL COMPANY 


Partitions: 

In partition construction lath is attached to steel 
studs by wiring through holes punched in flanges for that 
purpose or when hot or cold rolled channels are used a,§ 
studs, wire is passed entirely around the channels. No. 
18 gauge galvanized tie wire is commonly used for tying 
steel lath where this method must be employed. 

The following table shows the number of spring clips 
for one layer of lath per ton of various sizes of steel joists, 
when used as recommended in preceding paragraphs. 
Quantity includes five per cent for waste. 


Number of Clips Required per Ton of Joists 


Size ot 

Joist 

Weight 
per foot 

Floors 

12* C. to C. 

Ceilings 

8* C. to C. 

12 

12.0 

180 

265 

11 

10.7 

200 

295 

10 

9.5 

220 

330 

10 

8.7 

240 

360 

9 

7.7 

275 

410 

8 

6.8 

310 

465 

7 

5.8 

365 

545 

6 

4.9 

430 

645 

5 

4.3 

490 

735 

4 

3.7 

567 

850 


Clips for various depth of joists are furnished in sizes 


as listed below: 

4, 5, 6 inch joists.3 inches wide 

7 inch joists.3^ inches wide 

8, 9, 10, (8.7 lb.) inch joists.4 inches wide 

10, (9.5 lb.) 11, 12 inch joists.4 y 2 inches wide 


Shipments are made in packages containing 1,000 
clips each. Average weight per 1,000 clips is 13 lbs. The 
clips become meshed together in the container. To 
separate simply lift and shake. The clips will loosen and 
fall to the floor. 


L 



















1 


THE NATIONAL PRESSED STEEL COMPANY 


BRIDGING 

Many Engineers and Architects believe that in steel 
joist construction the concrete slab above the joists gives 
sufficient distribution of concentrated loads for ordinary 
light occupancy buildings. We recommend, however, that 
bridging be used and particularly on the deeper joists. 
For the smaller joists on short spans and close spacing 
bridging is not required. 

The function of bridging is twofold. First, to hold the 
joists in an upright position and maintain the spacing 
prior to the placing of the lath. Second, to provide lateral 
rigidity and distribute concentrated loadings during the 
life of the building. 

To efficiently function for the first requirement the 
bridging does not need to be tight. If fastened to the 
top of the joists and installed more or less loosely as 
shown in sketch “A”, Page 53 it will hold the joists in 
place during that period before the installation of lath. 
Bridging installed in this manner is of no value after 
completion of the floor. 

For the bridging to provide lateral stiffness and aid in 
the distribution of loads it must be straight and taut 
between joists. Installed as shown in sketch “B,” 
Page 53. 



Continuous Bridging 


49 





































r 


THE NATIONAL PRESSED STEEL COMPANY 


There are two types of bridging. Continuous bridging 
has been used for a number of years. This material is 
twenty gauge steel one inch wide, furnished in coils. The 
continuous bridging is woven through the joists across 
the panel, then tightened up by pulling out the slackv 
This is a difficult operation and good work is secured only 
by giving it careful attention. In this method the bridg¬ 
ing is secured to the joists by nailing through the bridging 
into the joists both top and bottom. 



Single Strap Bridging 


Single strap bridging is a later development. In this 
method of bridging a single piece of eighteen gauge steel, 
one inch wide, is used. The bridging is furnished in four 
different lengths of straps which meet the requirements 
for every size and spacing of joists. See table, page 51. 
This type of bridging is easier to install than the continu¬ 
ous bridging. The material costs a little more but the 
saving in time and the greater efficiency more than makes 
up the difference. A heavier strap is used than in continu¬ 
ous bridging because the installation process permits and 
the greater strength provides for the distribution of 
greater loads. 


50 
































THE NATIONAL PRESSED STEEL COMPANY 


SINGLE STRAP BRIDGING 

Designation Letter 
for 

Standard Bridging Lengths 

Strap A—34 Y" long. 

Strap B—313/2" long. 

Strap C —21 Yl' long. 

Strap D—24" long. 


Steel Joists 

Spacing of Joists- 

—Center to Center 

Size 

Weight 

12" 

16" 

19" 

24" 

4 

3.7 

D 

D 

C 

B 

5 

4.3 

D 

D 

C 

B 

6 

4.9 

D 

D 

C 

B 

7 

5.8 

D 

D 

C 

B 

8 

6.8 

D 

C 

C 

A 

9 

7.7 

D 

C 

B 

A 

10 

8.7 

D 

C 

B 

A 

10 

9.5 

C 

C 

B 

A 

11 

10.7 

C 

B 

B 

A 

12 

12.0 

C 

B 

B 

A 


When ordering, give designation letter, as Strap “A.” 
Single Strap Bridging shipped in bundles containing 
25 straps each. 

Furnished in No. 18Ga. Black Steel. Average weight 
per bundle, 10 lbs. 


51 















































































THE NATIONAL PRESSED STEEL COMPANY 


Installing Single Strap Bridging 

To install single strap bridging lay the end of the 
strap over the top of a joist as in sketch “C.” Bend about 
1 at end down at right angles. On the other side 
of the joist bend the strap down approximately in line 
wdth the bottom of the next joist. Then as in sketch “D” 
put the bent end of the strap under the next joist. Bend 
the end clear around the lip or secondary flange of the 
joist. Pull the strap tight and bend down as shown by 
dotted line over the top of next joist. The bridging can 
be bent tight around the lip of the joist by using a claw 
hammer or other tool as shown by sketch “E.” 

In bridging a panel, first have the temporary wood 
strip in place near each line of bridging. Have each end 
joist in the panel anchored as shown on page 55. Then 
put clear across the panel all the straps of the bridging 
which run in the same direction. Start back with the 
cross straps, using the same method of applying. See 
sketch “F 

Before clinching the bridging to the top of each joist 
use a bar as shown by sketch “F.” With this bar pry the 
bottom of the joist “a” toward the joist “b”. After the 
bridging strap is clinched relieve the pressure and the 
bridging between those joists, including both straps, is 
very tight. The tightness of the bridging depending upon 
how much pressure is exerted on the bar. Care should 
always be taken to see that the joists are not pried out 
of a vertical alignment. 

See that the straps are well clinched around each lip. 
The bridging can then be nailed to the joists the same 
as in continuous bridging, but this is not necessary. 

Bridging put on in this manner will always give a 
good workmanlike job. The material will function in 
every respect. It cannot come loose or slip from the 
joists lips, particularly after the floor concrete and 
ceiling plaster have been placed. 


52 




THE NATIONAL PRESSED STEEL COMPANY 


















































THE NATIONAL PRESSED STEEL COMPANY 


INSTALLING STEEL JOISTS 

Steel joists leave the fabricating shop cut to proper 
lengths ready for installation. As the joists are placed 
they should be properly spaced in accordance with the 
erection diagram previously prepared. Care being taken 
to see *hat each end of each joist has level bearing and that 
they are in a true upright position. In order to hold the 
joists in place strips of wood should be temporarily nailed 
to the top of the joists immediately after they have been 
placed in position. See sketch page 55. These temporary 
wood strips, preferably not over one inch thick and two 
inches wide, nailed at right angles to the joists, should be 
placed one strip at each end of the joists and a strip 
approximately where each line of bridging is to be placed. 
The purpose of these strips is to save work of respacing 
and relining the sections, to hold the joists rigid while 
bridging is installed and make the floor more rigid for work¬ 
ing on before lath and concrete are applied. 

After the joists have been placed with the temporary 
wood strips holding them in position the bridging should 
be installed. Installation of the bridging is described on 
page "52. 

With the bridging and temporary wood strips in place 
the panel is sufficiently rigid to work on. Lay temporary 
sheathing over that portion to be used and proceed with 
other work on the building. It is best not to place the floor 
lath until shortly before ready to lay concrete, as the lath 
catches any debris which falls from work above. Before 
placing floor lath see that the joists are in a vertical posi¬ 
tion. Always place floor lath with the ribs up. Tear the 
temporary wood strips up just before placing lath. Fasten 
the lath to the joists with lath clips or large headed roofing 
nails. At each joist one clip in center of sheet and one at 
each side. Clip at side of lath should hold down edge of 
both sheets, page 44. After the lath is in place lay the 
concrete. The concrete mix depends upon the type of 
floor finish, page 143. Use just enough water so that the 
mix will not run through the lath. Never use gravel 
passing through a screen larger than Ceiling lath is 

then erected and slab is ready for ceiling plaster. 

I_ 


54 





Steel Joist Floor Panel 
Ready for Laying 


THE NATIONAL PRESSED STEEL COMPANY 



55 



















THE NATIONAL PRESSED STEEL COMPANY 


ESTIMATING DATA 

Assume a building designed with some other type of struc¬ 
tural layout. It is desired to determine the cost with Steel 
Construction. The determination of this cost involves an 
analysis of every structural portion of the building. 

First—Determine the exact area of every floor slab 
in the building. 

Second—Compile a tabulation of column loads on each 
column for each story down through the building to the 
footings, determining the total loading to apply on each 
footing. In every case making allowance for such load 
reductions as are permissible. 

Third—Design each footing determining the amount of 
excavation, reinforcing steel and concrete necessary, 
compare these results with the quantities called for accord¬ 
ing to other designs that may be specified. 

Fourth—Design the columns throughout the building. 
Determine the materials involved in fireproofing the steel 
column sections. If columns are to be fireproofed with 
plaster on Steel Lath compile the vardage of lath necessary. 
If fireproofed with clay tile determine the quantity of tile 
involved. 

Fifth—Design supporting beams and determine 
amount of materials involved in providing required fire 
protection. 

Sixth—Design stairways and window lintels. 

Seventh—Design Steel Lumber floor slabs. 

After determining the size of joists required in a panel 
the weight of joists can be taken from an actual prelim¬ 
inary layout or can be determined on the square foot basis, 
see graphs pages 58 to 61, table page 57. 

Add fi ve percent to the floor areas to determine the 
lath yardage, remembering that in most cases there are 
two layers of lath for each floor. Compute the cubic yards 
of concrete necessary for the two inch concrete slabs above 
the joists, also the yardage of ceiling plaster. The quan¬ 
tity of accessory items is determined according to data 
given in this book in connection with their description. 
Refer also to table of quantities page 62. 

A determination of the cost of Steel Construction is 
then secured by applying correct unit costs to all of the 
materials involved as indicated. In many instances 
more economical results in Steel Construction can be 
secured by re-arranging the column arrangements. If 
architectural considerations permit advantage should 
be taken of such economical opportunities. 




THE NATIONAL PRESSED STEEL COMPANY 


Pounds of Steel I Joist per Square Foot of 
Floor Area Required for Various Spacings 


National 

Steel 

I Joist 

Section 

Lineal Feet of Joist per Sq. Ft. Floor Area 

National 

Steel 

I Joist 

Section 

1.0 

.75 

.632 

.50 

Steel Joist Spacing 

12" 

16" 

19" 

i 

24" 

Pounds of Joist per Sq. Ft. Floor Area 

4" 

3.70 

2.77 

2.33 

1.85 

4" 

5" 

4.30 

3.22 

2.71 

2.15 

5" 

6" 

4.90 

3.68 

3.09 

2.45 

6" 

7" 

5.80 

4.35 

3.66 

2.90 

7" 

8" 

6.80 

5.10 

4.29 

3.40 

8" 

9" 

7.70 

5.77 

4.86 

3.85 

9" 

10" 

8.70 

6.52 

5.50 

4.35 

10" 

10" 

9.50 

7.12 

6.00 

4.75 

10" 

11" 

10.70 

8.02 

6.75 

5.35 

11" 

12" 

12.00 

9.00 

7.58 

6.00 

12" 


In estimating total weight of steel joist in a floor, 
figure area to include full length of joist. 


57 


























1 


THE NATIONAL PRESSED STEEL COMPANY 


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— O C7> <X> t" 



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58 


















































































































































































































































POUNDS OF STEEL JOISTS PER SQUARE FOOT 
FOR GIVEN LOADS AND SPANS 

dO/STS SPACED 1 6 ON CENTERS 


THE NATIONAL PRESSED STEEL COMPANY 


SONROd N! a\/01 3JVS 


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59 


Total Load includes weight of Floor Construction. 

Fibre Stress not exceeding 16,000 lbs. per square inch. 

In estimating total weight of Steel Joists in a floor, figure to include full length of joists. 














































































































































































































































































60 








































































































































































































































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THE NATIONAL PRESSED STEEL COMPANY 


ECONOMY OF STEEL CONSTRUCTION 

The economy of Steel Construction (Steel Lumber and 
Structural Steel) begins on the architect’s board. Simplici¬ 
ty in design and adaptability to desired architectural 
conditions relieve the architect for application to the 
planning features of the building. During erection the 
inspection problem is reduced. All through from first 
inception to final completion of structure the architect’s 
work is simplified and his efforts directed with more con¬ 
fidence. After completion the absolute certainty of the 
structural dependability assures the client’s satisfaction. 

The reduction in dead load of floor slabs in turn reduces 
the weight of beams, columns and footings. The saving 
in volume of materials to be transported, carted, hoisted 
and manhandled affects every structural portion of the 
building. The elimination of extraneous material cleans 
up the job and promotes greater efficiency of all workmen. 
The saving in time of construction enables the quicker 
occupation of the structure and shortens the period of 
investment without returns. Little economies in con¬ 
struction, such as scaffolding, false flooring and the like, 
total to respectable proportions. 

Every operation is always that much definitely ac¬ 
complished. Every trade once started works through 
steadily to completion of their work. Weather conditions 
have comparatively little effect on Steel Construction. 
The saving never ends. Low depreciation reduces annual 
upkeep expense The durability and permanence of a 
building is directly dependable on the efficiency of its 
structural basis. Time only emphasizes the advantages 
of steel. 

Economy does not mean cheap construction. None 
of the materials entering a building of this type are cheap. 
It is the efficient combination of materials, the taking 
advantage of their basic merits that results in an economi¬ 
cal and efficient design. The savings are impossible of 
complete 'visualization. They can be generally realized 
and best secured by designing in steel. 


63 




THE NATIONAL PEESSED STEEL COMPANY 


COST DATA 


Construction costs are very important to the owner and architect. 
Also this one point is the most difficult to resolve into the status of 
definite information. So many factors enter to effect the costs on 
each operation that the best advance determination is after all only an 
estimate. In giving information on costs we intend only to indicate 
the better methods of arriving at a reasonably accurate advance esti¬ 
mate and to particularly call attention to those more important 
factors involved which do materially effect the total expenditure. 


The unit costs used represent a general average over a large section 
of the country in March, 1921. It is improbable that at that time 
they would have applied on any operation anywhere. However, the 
percentage of variation between localities can not be large. When 
resolved into square foot costs it is even less obvious. The value of 
the data given lies in comparisons. The efficiency of one type of 
construction against another for certain conditions being clearly 
brought out. The use of unit costs actually applying locally will 
correct the total costs for that condition but will not materially effect 
the relative standing of various designs. 


No one type of construction can claim greater efficiency and 
economy under all conditions. Steel Construction (Structural Steel 
and Steel Lumber) is particularly adapted to the field of buildings 
with live loads running under 150 pounds per square foot and spans un¬ 
der 24 feet. T his line of demarkation is not fixed. Local conditions 
cause it to fluctuate. In the field described a close analysis will usually 
show the greater economy of steel. 

In making comparisons between steel designs and other types of 
construction our purpose is not one of criticism. In this volume we 
are only trying to develop all those points pertaining to Steel Designs 
which will be of interest to the building public. Realizing that the 
maximum efficiency of any type of construction can always be secured 
by originally planning for that design, we wish to indicate the proper 
method of initially determining wherein lies the greatest economy. 

The Architect, Engineer and Owner are necessarily in an unpre¬ 
judiced frame of mind. They are invariably seeking for real informa¬ 
tion reflecting to their own interests. Such information must be 
correctly based to be of value. We have therefore unhesitatingly 
shown the true conditions regarding costs applying to Steel Construc¬ 
tion. The effect of increasing spans and live loads on the cost of 
Steel Lumber floor slabs is clearly indicated on page 67. An analysis 
of how the square foot costs were determined for developing the curves 
is shown. 

The Steel Fabricating industry is in position to give further detailed 
information on this subject. 


64 





THE NATIONAL PRESSED STEEL COMPANY 


FLOOR SLAB COSTS 

The Floor Slab Cost Curve, page 67 indicates the effect of loads and 
spans on the cost of floors and shows a comparison of three types of 
floor construction. 

The curves were developed on the following designing basis:— 

1 

Fibre Stress—Steel 16,000 lbs. per sq. inch. 

Concrete 650 lbs. per sq. inch. 

Wood 1,200 lbs. per sq. inch. 

Moments —Concrete Joists W/ 

Fo 

Steel Joists and Wood Joists W/ 

IF 

Cost analysis per sq. foot 
60 lb. live load on 18 foot span. 


Concrete Joist Floors 

Detail shown on curve page 67 

Weight of material used—88 lbs. per sq. foot. 

3Vz B. F. form lumber at $35 M. ft.$0.12 

Labor of placing and tearing down.. ]0 

.3 cu. ft. concrete in place at $10.80 cu. yd.12 

2.4 lbs. reinforcing steel bent and placed at 5 cents lb.12 

6 in. terra cotta tile..14 

Placing terra cotta tile.03 

Concrete floor finish ( 3 4 in.).08 

Plaster ceiling—assuming smooth surface at 63 cents sq. yd.07 


Total cost per sq. ft. concrete finish floor surface.$0.78 


For Wood Floor Finish as detail A 


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Deduct concrete floor finish..08 


$ 0.70 

Add- 

Screeds—beveled and leveled.04 

Maple flooring finished.30 

Concrete fill between screeds. .07 

Total cost per sq. ft. with wood floor surface. $ 1.11 


65 























































THE NATIONAL PRESSED STEEL COMPANY 


FLOOR SLABS COSTS—Continued 

« 

Steel Joist Floors 


Detail shown on curve page 67. 

Weight of material used—37 lbs. 

3.8 lbs. steel lumber joists at 6.3 cents lb.30.24 

Steel lath (top and bottom) at 36 cents sq. yd. )08 

Labor placing joists and bridging.025 

Labor placing steel lath.025 

Ceiling 17 cents sq. yd. 

Floor 5 cents sq. yd. 

2 in. concrete fill.085 

Concrete floor finish (% in.).08 

Plaster ceiling at 86 cents sq. yd.095 


Total cost per sq. ft. concrete finish floor surface. $ 0.63 


For Wood Floor Finish as detail B 






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Detail B 


Detail B 

Deduct Vs of concrete fill.30.01 

Deduct concrete finish.08 

30.54 

Add- 

Screeds—plain—nailed to joists. .02 

Maple flooring finished.30 

Total cost per sq. ft. with wood floor surface.j.$0.86 

Wood Joist Floors 


Weight of material used—25 lbs. per sq. It. 

Wood joists in place at $45 per M. B. F.$0.08 

Wood ceiling lath in place at 27 cents per sq. yd..' .03 

7 /s in. sub-floor in place.07 

Bridging in place.01 

Finished maple wood flooring in place..30 

Plastered ceiling at 71 cents sq. yd.08 


$ 0.57 

For fire-safe floors where the live load is under 150 lbs. to the square 
foot, Steel Joist Construction is usually the more economical design. 
The saving in time of erection of the entire structure is a factor of 
economy^not shown in the above cost analysis. 


66 




































Curves Showing Relative Costs 
Concrete Joists—Steel Joists—Wood Joists—Floor Slabs 


THE NATIONAL PRESSED STEEL COMPANY 


vjhv acoujo±ooj 3 dvn 6 Q a 3 d 1303 



67 


SPAN IN FEET 

The reduction in dead load makes the saving. 




































































































































THE NATIONAL PRESSED STEEL COMPANY 


BEAM COSTS 

The Beam Cost Curve, page 69, indicates the effect of loads and 
spans on the cost of beams. It also brings out the relative cost of 
concrete beams supporting concrete floor constructions as compared 
with Steel Beams supporting Steel Joist floor construction. 

For the same position in a structure the total load applied oi\ the 
concrete beam will materially exceed the total load applied on the steel 
beam. For example:— 

Assume panels 16 x 20'—beam span 20'. Live load 60 lbs. 

Dead load steel joist floor—38 lbs. per sq. ft. 

Dead load concrete joist floor—84 lbs. per sq. ft. 

Total dead weight steel beam—1,250 lbs. 

Total dead weight concrete beam—7,600 lbs. 

Then total load applying on steel beam—32,610 lbs. 

Then total load applying on concrete beam—53,680 lbs. 

Cost of Eeams as shown on Curves 


Steel.$3.52 per lin. ft. 

Concrete. 4.15 per lin. ft. 


The difference in total load makes the saving. 

Analyzing Cost Curves at these Points 
Steel Beam—Cost per lineal ft. 


Beam 15"-42 lbs. } S1 lbs at 5 cents in place 
Shelf angles, 9 lbs. J 

Furring clips, channels, in place . 

3V2 sq. ft. lath in place, at 5 cents. 

Plaster 2"-3 */2 sq. ft. at 17 cents. 


= 32.551 r, • • 

I Projection 

= .20 ; below 

= .18 1 ceiling 7" 

= . 5.9J 


$3.52- 

Concrete Beam—Cost per lineal ft. 


17 lbs. Reinforcing steel at 5 cents.=$0.85] 

3.6 cu. ft. concrete at 45 cents.— 1.62 j Projection 

5 sq. ft. forms at 25 cents.= 1.25 [below 

5 sq. ft. of plaster at 8.5 cents.= .43 [ceiling 17" 


$4.15j 

Note that in figuring the quantity of concrete in the beam an 
arbitrary dimension of 6" for the T extension was taken. Depth of 
T same as floor thickness. This instance 8". 

Moment of W1 used in design of Steel Beam 

IT 

Moment of \V1 used in design of Concrete Beam. 

“To 

One very important factor is the projection of the beam below 
ceiling line. If the projection for the concrete beam was held to that 
of the Steel Beam it would greatly increase its cost. On the other hand, 
if a story clearance from floor to beams is to be maintained then the 
concrete beam necessitates an additional 10" on height of all walls, 
partitions, columns and risers in all piping. This difference in beam 
projection is an important factor to be considered in building costs. 

In determining the relative economy of beams in Steel Construction 
always compute the loads applying on the beams for various types of 
design. Take into account the effect of greater beam projection on 
costs of other parts of the structure and give full consideration to 
time saved in installation. 


68 
















Curves Showing Relative Costs Reinforced Concrete and Steel Beams 


THE NATIONAL PRESSED STEEL COMPANY 


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69 

























































































THE NATIONAL PRESSED STEEL COMPANY 


COLUMN COSTS 

The column cost curves, page 71, give relative costs of reinforced 
concrete and structural steel columns. A Steel Lumber and Structural 
design is of much lighter dead weight than reinforced concrete, and in 
using these curves full consideration must be given to this difference 
in dead weight. This will readily be seen from following example— 

Assume column supporting five floors—panel 20 ft. x 20 ft. 

Live load 60 lbs. per sq. ft. Dead load steel lumber floors—40 lbs. 
per sq. ft. 

Dead load concrete floors on concrete columns—90 lbs. per sq. ft. 
Weight of steel beam—1,200 lbs. 

Weight of concrete beam—12,300 lbs. 

Then total load on structural steel column—205,200 lbs. 

Then total load on concrete column—361,500 lbs. 

; . }...-: 

Cost of Columns as shown on Curves 

Steel 12 ft. high.33.53 per lin. ft. 

Concrete. 6.35 . 

The difference in total load makes the saving. 


Analyzing Cost Curves at these Points 
Steel Column—Cost per Lineal Foot 

10" Beth.—54 lbs. at 5 cents in place. 

3% sq. ft. Fireproofing at 25 cents. 

(Includes 2" cement plaster, metal lath and furring.) 


32.70 
. .83 


33.53 


Concrete Column—Cost per Lineal Foot 


36 lbs. reinforcing steel, at 5 cents in place.31-80 

4.27 cu. ft. concrete at 45 cents. 1.92 

7V 2 sq. ft. forms at 25 cents. 1.88 

7l/ 2 sq. ft. plastering at 10 cents.75 


36.35 

Further analysis will also show very marked saving in floor space 
by using steel columns. The finished dimensions of steel column are 
16 in. x 16 in., and that of concrete column 29 Vi in. in diameter. 

The saving is therefore 2.9 sq. ft. per column or 14 q sq. ft. on 
one floor of building 100 ft. x 140 ft. This saving in floor space is an 
important item which must be considered both as to cost and net floor 
space available. 

In determining the relative economy of columns in steel construc¬ 
tion always compute the loads applying on columns for various types 
of design. 

This reduction in load effects a very material saving. Freight, 
cartage, hoisting and placing a ton of material costs money. Also check 
the square feet of floor area taken up by columns and give this item 
consideration in the cost comparison. 


70 














Curves Showing Relative Costs Reinforced Concrete and Steel Columns 


THE NATIONAL PRESSED STEEL COMPANY 





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71 











































































THE NATIONAL PRESSED STEEL COMPANY 


FOOTING COSTS 

The footing cost curves page 73 give costs for various 
loadings. They are utilized to show the saving in support¬ 
ing a Structural Steel and Steel Lumber building as com¬ 
pared to a reinforced concrete building. The saving of dead 
w'eight over reinforced concrete in the steel lumber and 
structural steel building is considerable and should be fully 
considered in any cost comparison. The saving will readily 
be seen from the following example: 

Assume footing supporting five floors, panel 20' x 20'. 

Live load 60 lbs. per sq. ft. 

Dead load steel lumber floors 40 lbs. 

Dead load concrete floors 90 lbs. 

Weight of steel beam 1,200 lbs. 

Weight of concrete beam, 12,300 lbs. 

Total weight struc. steel columns fireproofed, 9,000 lbs. 

Total weight reinforced concrete columns, 30,000 lbs. 


Then total load steel lumber design.214200 lbs. 

Then total load concrete design.391500 lbs. 

Cost of footings as shown on curves, soil pressure, 
6,000 lbs. 

Steel Lumber and Structural Steel.#30.00 

Reinforced Concrete. 72.00 

Analyzing Cost Curves at these points: 

Steel Lumber and Structural Steel Building— 

71 cu. ft. excavation at 5 Y 2 cents.# 3.90 

15.8 sq. ft. forms at 15 cents. 2.37 

60.3 cu. ft. concrete at 30 cents. 18.09 

131 lbs. reinforcing steel at 4.3 cents. 5.64 


#30.00 

Reinforced Concrete Building— 

179 cu. ft. excavation at cents.# 9.84 

29 sq. ft. forms at 15 cents. 4.35 

150 cu.ft. concrete at 30 cents. 45.00 

298 lbs. reinforcing steel at 4.3 cents. 12.81 


#72.00 

These costs are based on ordinary earth excavation. 
If the footings run into a harder earth classification the 
difference in cost is more pronounced In a building 100' 
x 140' the example given develops a saving of #2,016.00 for 
footings alone. In determining the relative economy of 
Steel Construction always give careful consideration to 
the effect of decreased dead load on footing costs. 


72 

















Curves Showing Costs Reinforced Concrete Footings 


THE NATIONAL PRESSED STEEL COMPANY 



CtfVllOO N'/ 9NUOOJ 313H0N0D JO 1000 1V101 


73 


100 140 180 220 280 300 340 380 420 460 500 540 580 620 660 700 740 

COLUMN LOAD IN THOUSANDS OF POUNDS 

The reduction in total load makes the saving. 












































































































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 

In the design of Steel Lumber the development of 
details of construction involves the application of common 
sense in the use of a material lending itself to definite 
designing. 

The supporting member is in every instance rigidly 
framed in place. The steel joists are rigidly braced by 
the balance of the floor construction. All transfer of 
stresses from joists to supporting members is vertical. 
The finished floor construction forms a rigid slab of which 
the supporting girders become an integral part. There 
is absolutely nothing to be gained by direct connection 
of the joists to the girders. The details as shown are 
efficient and have become common practice through many 
years of use. 

It is impractical to attempt in this book to show all 
construction details for every purpose. It is intended 
that the general principles be clearly brought out, thus 
enabling the designer to intelligently detail any particular 
problem. It is well to remember that steel joists have 
been developed for the carrying of lighter loads, and 
they cannot economically compete with the heavier struc¬ 
tural sections in the field of heavier loads. 

The intelligent design of steel joist floors requires that 
due consideration be given to such details in building 
construction as plumbing, heating and wiring. Proper 
layouts of framing plans will develop economy in the 
installation of these items. 

In the interest of economy it is well to guard against 
any unnecessary fabricating, such as notching, levelling 
and punching. A large percentage of the fabricating on 
National Steel Lumber Sections involves only cutting to 
length. This simplicity in design, fabricating and erec¬ 
tion constitutes one of the important factors in the 
value of National Sections. 


74 


I 




THE NATIONAL PRESSED STEEL COMPANY 



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75 





















































THE NATIONAL PRESSED STEEL COMPANY 


Girder support with joists resting on shelf angles. Wood floor finish. 


CONSTRUCTION DETAILS 


Girder support with joists resting on shelf angles. Cement floor 
finish. 


76 




















THE NATIONAL PRESSED STEEL COMPANY 




CONSTRUCTION DETAILS 



Non-firesafe floor. Wood sheathing nailed directly to the joists 
Joists resting on top of girder and lapped with strap bridging tie. 



Tile finish floor with beam clips holding joists to top flange of girder. 


77 


A 











































---1 

THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION 

DETAILS 

V 


Steel stud bearing parti¬ 
tion support, showing con¬ 
nection at break in studs. 


Showing two inch sol¬ 
id plaster and steel lath 
non - bearing partition, 
conduits and water 
pipes, with wood floor 
finish. 


78 

























































THE NATIONAL PRESSED STEEL COMPANY 


Showing 2 ” 
solid plaster 
on steel lath, non- 
bearing partition 
and conduits with , 

cement or tile floor finish. 
Rolled angle partition plate 
anchored to concrete fill with 
expansion bolt. 


CONSTRUCTION 

DETAILS 


Showing hollow tile 
non-bearing partition, 
conduits and soil pipes. 
Tile partition built on 
top of 2" concrete fill. 


79 
































-, 

THE NATIONAL PRESSED STEEL COMPANY 


Framing Around Small Openings 

Framing around small openings such as ventilating 
ducts and chimneys requires only steel joist. Where the 
header connects with the trimmer simply flatten the lip 
with a tool shaped as shown, (Pipe wrench). Pound the 
end of the trimmer with a sledge, fit the sections together 
and connect the flanges top and bottom as shown, using 
four soft rivets or stove bolts. 

Further description of this detail is given on page 125. 


CONSTRUCTION DETAILS 


80 











-, 

THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 


Framing Details 

Framing around large openings such as stairwells 
requires structural steel headers and trimmers. In most 
cases the light weight structural channel the same depth 
as the joists will carry the loads. Standard connection 
details are used. The steel joist trailers being supported 
on shelf angle riveted to the back of the header channel. 

Refer to pages 125 to 127 for tables and further descrip¬ 
tion of this detail. 


81 

























THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 


C 

| ‘ 


; 

v 1 

-~—5TCCL-ISTUD 

« SSTCEL LATH 

iillllCPOORjII'lllllll 



t*'-- ; - r —-1 


i - ms 


SCOT!ON SHOWING COUGH UOOCT 

BucK < £ nn/sHOD door jams 



section showing hailihg 

strips roe mood base board. 


Bearing Partitions 

In certain types of buildings where the design is very 
regular, bearing partitions can sometimes be economically 
used in place of columns and beams for supporting the 


82 












































































































































































THE NATIONAL PRESSED STEEL COMPANY 


Bearing Partitions —Continued 

floors. For these partitions attention is called to the 
framing of the studs around doors and windows. The sill 
and cap plates at the top and bottom of the partition 
studs are the special four inch channel section shown on 
page 20. The studs are connected to these plates top 
and bottom with rivets or stove bolts. 

For wide openings where the load applied is sufficient 
to cause more than the allowable deflection in members 
spanning the opening, special support must be provided. 
The best detail for this special support is the use of No. 8 
wire placed and twisted as shown. 

In laying out the framing plans for partitions or walls, 
first make a detail of the standard openings. This detail 
can simply be indicated at the locations desired and 
straight studs spaced in between. Ordinarily the fabri¬ 
cator furnishes the studs cut to length and the punching 
of bolt holes is done in the field with a hand punch. 

On large installations it is more economical to spot weld 
the sections, using a portable gas tank outfit. Sections 
of the same size are fitted into each other as described on 
page 80. The customary size of studs is four inch, using 
either the channel or I section as required by the loading. 

When channel^ sections are used, holes are punched in 
the flanges with a hand punch at approximately eight inch 
c enters. The steel lath is then wired to the [channels. 
. When I studs are used the lath is secured to the stud with 
the spring lath clip. 

The details for door jambs and window frames are simi¬ 
lar to those used in wood frame construction. See details 
shown. 

A steel stud and lath bearing partition carries a surpri¬ 
singly heavy load and provides an economical firesafe 
partition and wall construction. 


83 




THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



Where joists of different 
depths are supported on a 
channel section the floor 
level is maintained by 
using shelf angle to sup¬ 
port the deeper joist. 


Where the depth of 
joist and supporting gir- 
der does not permit the 
shelf angle flange extend¬ 
ing down, the angle is 
reversed as shown. Care 
being taken to cut the 
joists shorter so that 
ample clearance for leg 
of shelf angle and rivet 
heads is provided. 




Joists supported on ma¬ 
sonry walls should always 
have at least four inch 
bearing and not less than 
one-half the depth of the 
joist. 


84 







































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



Where the flange of 
supporting girder is suffi¬ 
ciently wide the joists 
can be butted and held in 
place by using beam clips. 


The usual method of 
supporting the joists is 
by using a shelf angle 
riveted to the web of the 
girder. This reduces the 
beam projection below 
ceiling line. 



Showing steel joists 
set on top of support¬ 
ing girder, with joists 
lapped. Strap t i e 
nailed to top of each 
joist holds them in 
vertical position. 



L 


85 


































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



A common method of 
anchoring joists to mason¬ 
ry walls is to turn bridging 
around anchor bar as 
shown and nail to joist. 

Standard practice calls for 
an anchor at every fourth 
joist. 


One method of anchor¬ 
ing the joist to masonry 
walls is to punch a hole 
in web and insert anchor 
bar. Bar may be bent 
back into wall. 


A temporary wood strip 
should always be nailed 
to joists when first placed. 
This strip holds the joists 
in position until bridging 
is installed. 


86 





































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 






" 1 ~ n 



• 


oi 





r 

4 


M 






When the joists are set 
in a brick wall, cement 
mortar should be slushed 
in around the joist to 
insure a tight job. 


When it is desired to 
have the top of joists level 
with the top of supporting 
girders, the top flange of 
the joists is beveled or 
coped out as shown. An 
oblique bevel cut simpli¬ 
fies fabrication, thereby- 
reducing cost and has 
proven equally as efficient 
as the notched cope. 


$evel Copep C^fyuareCope 

-- 



tdgmg Tie 



/TEEL \ 
I-JOi/T 


Joists are tied end to 
end as shown with bridg¬ 
ing nailed to the joists. 


87 


















































































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 




Joists lapped. 




i||l | l|ll|j|l|jl!lll!ll![j|l|j!ljl!l[l!l 

' STEEL 

I JOIST 

< 

) 




Joists butted 


Details for Methods of Supporting Joists. 


88 



























































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 







Details where steel joists are supported on Lintels in 
masonry walls. 



Steel Joists of different sizes set on shelf angles. 


89 









































































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 




Locating Shelf Angle for Joist Bearing 


The position of shelf angle on steel beam should be so 
located that top of joist will come close to underside of 
beam flange. 

Table shows the maximum depth of steel joist that will 
frame into different structural beams when vertical leg 
of shelf angle extends downward as shown in sketch. The 
dimensions given allow ample clearance at end of joist for 
quick and easy erection. 


Framing Dimensions for Shelf Angle Location 
When Leg is Down. 



1 



Distance From 



Standard 

I 

Beams 

Bethlehem 

I 

Beams 

Size of Angles 

Max. Depth 
Steel Joist 

Angle to Top 
of Beam 

Joist to Top 
of Beam 

Beam to Fin.- 
Floor 

Clearance at 
End of Joist 

Thickness of 
Standard Flooi 

A 

A 

B 

C 

*' 


- 

G 

H 

8"@18.41bs. 

8" @17.51bs. 

3x2V 2 xV 4 

4" 

4 3 / 4 " 

3/4" 

2 Vs" 

34" 

2 Vs" 

9" @21.81bs. 

9"@20.01bs. 

3x2V 2 xV 4 

5" 

5 3/ 4 " 

3 / 4 " 

2y 8 " 

3/4" 

2 Vs" 

Kr@25.41bs. 

10" @23.51bs. 

3x2 y 2 x Vi 

6" 

6 3>4" 

34" 

2y 8 " 

V." 

2 74" 

12" @31.81bs. 

12" @28.51bs. 
15" @38.01bs. 

3x2 y 2 x Vi 

7" 

8" 

1" 

Ws" 

3/4" 

2 Vs" 

15" @42.91bs. 

18" @48.5lbs. 

3x2y 2 xV 4 

10" 

11" 

1" 

174" 

34" 

2 Vs" 
2 Vs" 

18" @54.7lbs. 

20" @59.01bs. 

3x2y 2X y 4 

12" 

i 3 y 8 " 

1 Vs" 

1 3 / 4 " 

34" 

20" @65.41bs. 

24" @73.01 bs. 

3x2y 2X y 4 

12" 

i 3 y 8 " 

1 Vs" 

l 3 /!" 

Vs" 

2 Vs" 

24" @79.9lbs. 

26" @90.01bs. 

3x3 xVi 

12" 

In y 4 " 

1 y 4 " 


1" 

2%" 


i><) 































































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



G 4m c or beam 

L 



JOIST MUST REST^ 

ort Cleg • 


A 


^FINISHED FLOOR 


Locating Shelf Angle for Joist Bearing. 


When depth of joists approximates the depth of steel 
beam so that vertical leg ot shelf angle cannot extend down¬ 
ward, the shelf angles are reversed as shown in sketch 
above. In this case the length of joists should be slightly 
shorter than in detail on preceding page to allow clearance 
for thickness of angle and protruding rivet heads. 


Framing Dimensions for Shelf Angle Location 
When Leg is Up. 






Dista 

nee F 

rom 



Standard 

I 

Beams 

Bethlehem 

I 

Beams 

Size of Angles 

Max. Depth 

Steel Joist 

Angle to Top 
of Beam 

Joist to Top 
of Beam 

Beam to 

Finished Floor 

Clearance at 

End of Joist 

Thickness of 
Standard Floor 

A 

A 

B 

C 

D 

E 

F 

G 

H 

8" @18.41 bs. 

8" @17.51 bs. 

3x2y 2X y 4 

6" 

6 y 4 " 

34" 

2 Vs" 

1 Vs" 

2 Vs" 

9"@21.81bs. 

9" @20.01 bs. 

3x21 :/ 2X y 4 

7" 

7 3 4" 

34" 

2 Vs" 

1 Vs" 

2 Vs" 

10"@25.41bs. 

10" @23.51bs. 

3x2 Vi 

8" 

r'V' 

OO 

3 4" 

2 Vs" 

1 Vs" 

2 Vs" 

12"@31.81bs. 

12" @28.51bs. 
15" @38.01 bs. 

3x2 j /2xV4 

10" 

10 3 / 4 " 

34 " 

2 Vs" 

1 Vs" 

2Vs" 

15"@42.91bs. 

18" @48.51bs. 

3x21/2x1/4 

12" 

12%" 

Vs" 

2" 

1 Vs" 

2 Vs" 

18" @54.71 bs. 

20" @59.01bs. 

3x2 1 / 2 x 14 

12" 

13" 

l" 

1 Vs" 

1 Vs" 

2Vs" 

20" @65.41 bs. 

24" @73.01bs. 

3x21/2x14 

12" 

13i/«" 

1 Vs" 

1 3 4" 

1 Vs" 

2 Vs" 

24" @79.91bs. 

26" @90.01 bs. 

3x3 x 14 

12" 

1314" 

1 Vi" 

1 %" 

1 Vs" 

2Vs" 


91 





























































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



Details showing the various methods of anchoring joists 
to walls. The end joists in a panel should always be 
anchored laterally. 


92 






























THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



Nail tfle bridg¬ 
ing strap to the 
joist with 6d 
nails. 


For > support¬ 
ing air ducts, 
pipes, etc., use 
coiled bridging 
as shown in the 
details. For 
pipes hung be¬ 
low the joists a 
bar may be sup¬ 
ported on the 
bottom flange of 
two joists 
around which 
the strap hanger 
is fastened, or a 
bridging strap 
fastened to the 
top of joist as 
shown. 



93 


















































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 


Details showing Piping. Screeds and Outlet Box 

Support 

Various methods are'employed to work out this detail. The shape 
of the joist section and the open spac'e between the joist afford ample 
facility to carry out any of the methods commonly used. 


When the floor finish is cement or tile it is best to lay piping'before 
lath is placed. This gives a^continuous reinforcing to the slab and 
prevents cracks over pipes. 


94 


































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



Electric conduits and other small pipes are laid on top 
of the joists and buried in the concrete fill. Larger pipes 
are placed in space between joists when running parallel 
with the latter. When running at right angles to joists, 
pipes are hung with standard pipe hangers, steel straps 
or bridging as shown in the cross section above. 

Where pipes extend below the joists the ceiling lath and 
plaster is suspended. The floor construction permits the 
economical covering of all piping. 


95 










































CONCRETE 0N5TEEL LATH 


PLANKx 


■SPRING 

CLIP 


STEEL I JOIST 


METAL BRIDGING 


CONCRETE CM STEEL LATH 


THE NATIONAL PEESSED STEEL COMPANY 


Bearings for steel joists are provided 
by rolled steel angles built on top of steel girder or beam 
to form the desired contour of steps. Joists are secured 
to supports as shown and the concrete slab applied on 
metal lath as in standard floor construction. 


~ir 


Balcony or 
Grand Stand 
Construction 


96 













































































THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 


Suspended Ceilings 

When the architectural features of a building make a 
suspended ceiling desirable, the ceiling lath is attached by 
tie wires to a frame work constructed as shown. 

Either hot or cold rolled channel sections are used for 
this frame work. The sections are wired together in the 
field, making a rigid frame for the lath. 


97 





















THE NATIONAL PRESSED STEEL COMPANY 


CONSTRUCTION DETAILS 



Longitudinal section through sloping roof or balcony 
construction. 




Cross Section through roof or balcony construction 
when'supporting'girders are on a slope. 





98 







































THE NATIONAL PRESSED STEEL COMPANY 



CONSTRUCTION DETAILS 


attic floor 


WITH fllDGl bEAMOMlTTCD 


A 



DETAIL AT-A 



Df TAIL AT-C 

Roof Construction 

Details of steel joist hip roof construction. 


99 


> ) > 







































CONSTRUCTION DETAILS 


THE NATIONAL PRESSED STEEL COMPANY 



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100 

























































CONSTRUCTION DETAILS 


THE NATIONAL PRESSED STEEL COMPANY 



101 
























1 


THE NATIONAL PRESSED STEEL COMPANY 


STAIRWAY CONSTRUCTION 

In framing around stairwells, structural steel beams are 
used as header members, the sections coming at the foot 
and head of all stair, runs being designed to carry stairway 
loadings. 

There are many different types of stairway construc¬ 
tion, choice being governed by the type of building, loca¬ 
tion of stair and artistic effect desired. 

Wood Stringer Construction 

Where this fire retarding design is permitted, heavy, 
well seasoned, wood stringers can be placed with ends 
framing into supporting beams top and bottom of stair 
run. Steel lath to be nailed directly to and underneath 
these stringers, and this lath then plastered to a thickness 
of 1 /8 inches with approved plaster. Wood stair blocks 
nailed to the stringers may be finished directly with wood 
risers and treads or covered with steel lath and concrete, 
finishing either in concrete or wood. This type of stair 
is simple in design and easily constructed, but does not 
meet the requirements of a fireproof building. 

Concrete Construction 

After building forms for concrete stairs, the main rein¬ 
forcing rods are placed lengthwise with the stair run and 
hooked over supporting beams. The placing of and size 
of reinforcing bars to provide against shear and bending 
stresses is a matter of design in each instance. Concrete 
stair design can be adjusted to most any condition and is 
readily adapted to change in plans. The form construc¬ 
tion is more or less complicated and the dead weight of 
the stair runs is comparatively high. Concrete stairs 
comply with the requirements of fireproof buildings and 
when properly installed give excellent service. 

Pressed Steel and Ornamental Iron 

1 here are many designs of Pressed Steel and Ornamental 
Iron stairways on the market. Their popularity is due to 
light weight, ease of installation, simplicity, beauty, 
economy and durability. In connection with a structural 
steel skeleton frame a stairway of this type is the most 
practical. 

For many purposes stairs can be economically con¬ 
structed, using Steel Lumber sections. The following 
cuts show three designs, all of which give good substantial 
economical stairs. 


102 




THE NATIONAL PRESSED STEEL COMPANY 


STAIRWAY CONSTRUCTION 


LANDING 



Joist Type 

For stair construction to sustain unusually heavy loads this design 
is particularly adaptable. Supporting joists are placed as close as 
desired This design is simple in construction, the strap brackets 
being riveted on to the stringers in the fabricating plant. 


103 
















































THE NATIONAL PRESSED STEEL COMPANY 


STAIRWAY CONSTRUCTION 



'A mm 









Channel Type 

This stairway is fabricated in the structural steel shop and is 
installed at the building very rapidly. The treads can be finished 
in concrete tile or composition. The underside can be protected by 
plaster on steel lath or left uncovered as shown on the cut. The run is 
supported by structural steel channels on either side, clip angles being 
riveted in proper position on the back of the channels. The risers give 
support lengthwise with the tread sufficient for stairway width of ten 
feet. 





































THE NATIONAL PRESSED STEEL COMPANY 


STAIRWAY CONSTRUCTION 


Standard Type 

This design is similar to the standard steel joist floor construction, 
the nailing strip being diverted into the stair horses which are securely 
nailed to the I Joist Stringers, the details of the construction being 
clearly shown in the cut. This is a good, general purpose stair design 
and can be completely fabricated right on the job. 

The use of Steel Lumber sections in stair construction is rapidly 
becoming more universal. The adaptability of these three designs to 
all conditions, the light weight and economy make them the more 
desirable type for use in fireproof buildings in connection with structural 
steel skeleton frame. 


105 





































THE NATIONAL PRESSED STEEL COMPANY 


FIREPROOFING OF STRUCTURAL STEEL 

In building designs the most desirable material for the 
structural portions is that utilizing the least space and 
supplying the required strength with greatest certainty. 
Obviously steel answers the purpose. Its dependable 
uniformity, simplicity in design, rapidity of erection, 
adaptability to all conditions and rugged durability com¬ 
bine to give it recognition as the most practical material. 

Experience has proven that to meet exacting fire con¬ 
ditions it is necessary to protect structural steel sections 
against temperature conditions exceeding 700° F. This 
protection may be provided in many different ways—some 
of which are exceedingly expensive without comparative 
efficiency. " 

Many tests have been carried on by the more reputable 
laboratories of the world to determine better practice in 
fireproof construction. Such tests are conducted however 
under serious handicap. They cannot control actual field 
construction practice which in certain materials varies 
directly as the human equation. Actual fire conditions 
cannot be duplicated in test furnaces. Actual stressing 
conditions during high temperature fires, recognizing the 
possible effect on all portions of the building, can hardly 
be imagined much less duplicated in laboratory tests. 
Results of such tests are however of great value and give 
the fireproofing engineer added confidence in developing 
practical fireproofing designs. 

In actual fire conditions temperatures are applied 
unevenly and intermittently. For instance a certain 
column may have a high temperature existing near the 
ceiling and very low temperature near the floor. Later 
this condition may be reversed. The temperature may be 
applied against one side of the column and nearly normal 
temperature exist on the other side. A study of the action 
of structural steel shapes under high temperatures de- 
velopes that uneven temperatures have far more effect 
on the section than even temperatures. 

Heating of only the bottom flange or of one end of an 
I beam causes more distortion than when the heat is 
uniformly applied over the entire section. Therefore one 
of the first problems in fireproofing is to equalize this 
uneven application of heat of actual fire conditions. 
This may be accomplished by using expensive volume or 
mass of fire retarding materials of such thickness that the 
heat cannot penetrate. This practice however calls for 
the exercise of judgment, as all fire conditions present the 


106 





concrete floor | wood Floor 


THE NATIONAL PRESSED STEEL COMPANY 





107 


Standard construction does not call for fireproofing between the joists above the shelf angle but where 
requited it is provided as shown. 









































































THE NATIONAL PRESSED STEEL COMPANY 


1 


probability of the application of fire streams under 
pressure. Many materials capable of resisting high tem¬ 
perature cannot, regardless of volume, stand up under the 
combination of high temperature and water applied under 
pressure. 

The most efficient, and certainly the most economical 
method of equalizing uneven temperatures, is by use of the 
air space. A beam completely encompassed on both sides 
and underneath with an air space not less than one inch 
thick under the lower flange cannot be heated much in 
excess at any one point. If high temperature is applied 
at one end on the lower flange it is in time going to develop 
increase in temperature on the inside of the fire protection. 
With the air space this increase in temperature will be 
immediately distributed over the entire section. An 
enormous amount of heat must be applied on any given 
area in order to develop a material increase in temperature 
throughout the extent of the air space around the section. 

The next point for consideration is the type of fire 
retarding covering to use. Aligning the desirable features 
the following conditions fully met would represent a truly 
satisfactory condition: 

(1) Low Depreciation under Maximum Fire Conditions. 

This calls for rugged resistance under combined appli¬ 
cation of high temperatures and water. Minimum of 
expense to repair back to pre-fire efficiency. 

(2) Maximum Protection. 

Accepted standards of maximum fire conditions call 
for application of 1700° F. for four hours followed with 
application of 1 Y%" fife streams under 85 pounds nozzle 
pressure. "This condition is of course very unusual in 
actual fires but gives a good gauge for determining fire 
retarding efficiency. The protection used should hold the 
temperature in the air space to less than 600° F. 

(3) Thickness of Material. 

If for nothing more than commercial reasons it is 
desirable to use even at higher cost that design of protec¬ 
tion taking up the least area. 

(4) Simplicity of Installation. 

The elimination of the personal element in construction 
work always gives greater uniformity and security in 
results. That form of protection presenting the simplest 
construction problem and permitting the more positive 
inspection will always give the more uniform service. 

(5) Economy. 

In the last analysis costs always enter as a deciding 

I_ 


108 





; 

THE NATIONAL PRESSED STEEL COMPANY 


Fireproofing Structural Steel Beams 

Steel Joist Supported on Top Flange 





Column Fireproofing 

The fire protection is rigidly secured to the steel section. The 
result is a combination of materials providing the most rugged 
resistance to high temperature fire conditions. 


109 








































































































THE NATIONAL PRESSED STEEL COMPANY 


factor in the type of construction. That protection afford¬ 
ing the desired efficiency at the least cost will be more 
universally used and developed to the highest standard 
of general practice. 

Hollow clay tile three to four inches thick is accepted 
as efficient fire protection to columns and beams. This 
material provides an easy means of securing the dead air 
space around the section in case of columns. For beams it 
is more difficult to apply without fitting snug to the sec¬ 
tion. The depreciation of the protection is rapid under 
combined heat and water conditions. Tile does not ex¬ 
pand under high temperatures in the same proportion as 
steel. In column protection this results in cracking of the 
tile protection near the top of the column. Tile does 
however give measurably good protection and is easily in¬ 
stalled at a reasonable cost. 

Cement plaster on steel lath provides a rugged efficient 
fire barrier, see page 7. The plaster ranging from one 
inch to two inches in thickness as requirements necessitate. 
The air space around sections is secured by proper furring 
for either columns or beams. The rigid installation of 
lath is a simple operation. The lath expands and con¬ 
tracts with the steel section and distributes this stressing 
uniformly over the area of the plaster. The cement 
mortar mixed with sufficient hydrated lime to give pro¬ 
per plastic condition is applied in successive coats to de¬ 
sired thickness. 

The resistance of this protection to most exacting condi¬ 
tions is remarkable. Total destruction at any point is 
most unusual. Expense of restoring is a minimum. It 
provides the proper protection most satisfactorily— 
standing up under maximum artificial conditions from 
two to four hours and in actual conditions going straight 
through the most intense fires with unimpaired efficiency. 
Plaster on steel lath protection is the most scientific, 
takes up the least space, shows relatively higher efficiency 
under all actual fire conditions and is installed at a cost 
within the range of all builders. Cement plaster on steel 
lath is a good method of fireproofing structural steel. 
It is adaptable to all locations and types of buildings. 
Details of application are shown on pages 107 and 109. 


110 





THE NATIONAL PRESSED STEEL COMPANY 


FOOTING DESIGN 


The following tabulated information has been developed 
for the purpose of aiding in the design of simple footings. 
The method of design is that recommended by the Uni¬ 
versity of Illinois. The application of this design is illus¬ 
trated by example. 


Unit stress in concrete. . . 

Unit stress in steel. 

Unit bond stress. 

Unit punching shear. 

Unit bearing of steel plate 


650 lbs. per sq. inch 
16,000 lbs. per sq. inch 
100 lbs. per sq. inch 
120 lbs. per sq. inch 
500 lbs. per sq. inch 



^Assume a column load of 
600,000 lbs., soil pressure of 
8,000 lbs. per sq. ft., Weight of 
footing 390 lbs. per sq. ft. 

The net soil pressure will be : 
8,000—390=7,610 lbs. per sq.ft. 
The area of footing will be : 


600,000 

7,610 


=79 sq. ft. 


Make footing 9'0" square. 

Allowing 500 lbs. per sq. in . 
for bearing the area of stee 1 
base plate will be: 


600,000 

500 


=1200 sq. in. 


Make plate 35" square. 

Make top of footing 39" 
square to give good full bearing 
for plate. 

The effective depth of the 
footing equals the column load 
less the weight of the footing, 
divided by the perimeter of the 
base plate multiplied by the 
unit punching shear. 

600,000 - (81 X390) ... 

35X4X120 = 34 m - 

To this effective depth add 
3" for protection of steel, giv¬ 
ing a total depth of 37". 


Ill 

















































THE NATIONAL PRESSED STEEL COMPANY 


The center of gravity of the projecting side of the footing = 


(2.92X3.04) 


of (3.04)2 


2.92 + 3.04 


1.78 ft. 


The Bending Moment = 


+ 92 + 9 
2 


X3.04X7610XL 78 =243,000 ft. pounds. 


The resisting moment for the steel per sq. in.= 


16.000 X. 87 X2.83=39,400 lbs. 


As= 243,000 
39,400 


= 6.17 sq. in. =20 — Y a " round 


bars. 


The number of bars necessary to hold within the unit bonding 
stress of 100 lbs. per sq. inch equals: 

The perimeter of a Ys" round bar=1.96 in. 


2.92+9.0 


X3.04 X7610 


100X1.96X87X34 


24 bars. 


Therefore 24 -^" round bars 8'9" long will be used in each direc¬ 
tion. 

The tables give quantities of materials involved in footings under 
various loadings for soil pressure values of 4,000, 6,000 and 8.000 lbs. 
per sq. ft. 


Good engineering calls for a footing design that amply provides for 
the loads applied. Under-designing is dangerous and over-designing is 
useless waste. In making an alternate design always re-design the 
footings and insure obtaining the full economy in the use of steel. 

Inherent merit in materials used has a great deal more to do with the 
strength and durability of a structure than does mere bulk and weight. 


112 










THE NATIONAL PRESSED STEEL COMPANY 


FOOTING TABLE 



Soil Pressure 
4000 lbs. per. sq. ft. 




Col. 

Minimum 

Area 


C 

D 

E 

Round 
Bars Each 

Wt. 

of 

Volume 

A 

Load 

Base 

Plate 

B 

Way 

Steel 

Lbs. 

OI 

Concrete 




Sq. In. 





No 

Size 



Cu. Ft. 

4'- 

-0" 

62,000 

121 

10 

5 

14 

15 

9 

l A" 

45 

5 

17 

0 

4'- 

-6" 

78,000 

144 

10 

6 

15 

16 

11 

l A" 

62 

5 

22 

2 

5'- 

-0" 

96,000 

196 

11 

6 

17 

17 

12 

l A" 

77 

0 

29 

8 

5'- 

-6" 

116,000 

225 

12 

7 

18 

19 

13 

A" 

91 

5 

38 

7 

6'- 

-0" 

138,000 

256 

13 

7 

19 

20 

14 

'A" 

104 

0 

49 

4 

6'- 

-6" 

161,000 

361 

13 

7 

22 

20 

16 

V2 

134 

0 

59 

9 

7'- 

-0" 

186,000 

361 

15 

7 

22 

22 

17 

w 

154 

0 

76 

3 

7'- 

-3" 

200,000 

400 

15 

8 

23 

23 

18 

H” 

170 

0 

84 

3 

V- 

-6" 

214,000 

441 

16 

8 

24 

24 

19 

X A" 

185 

0 

94 

5 

T- 

-9" 

228,000 

441 

16 

9 

24 

25 

19 

l A" 

191 

0 

103 

0 

8'- 

-0" 

240,000 

484 

16 

9 

25 

25 

21 

l A" 

218 

0 

110 

9 

8'- 

-3" 

255,000 

529 

16 

9 

26 

25 

23 

W 

246 

0 

117 

7 

8'- 

-6" 

272,000 

576 

17 

9 

27 

26 

24 

V? 

266 

0 

132 

0 

8'- 

-9" 

288,000 

576 

17 

9 

27 

26 

16 

w 

283 

0 

140 

8 

9'- 

-0" 

303,000 

625 

17 

10 

28 

27 

17 

w 

310 

0 

150 

8 

9'- 

-3" 

318,000 

625 

18 

10 

28 

28 

18 

w 

338 

(1 

165 

9 

9'- 

-6" 

333,000 

676 

18 

10 

29 

28 

19 

w 

366 

0 

175 

2 

9'- 

-9" 

352,000 

676 

18 

11 

29 

29 

19 


376 

0 

190 

4 

10'- 

-0" 

370,000 

729 

18 

11 

30 

29 

19 

w 

386 

0 

199 

0 

10'- 

-3" 

388,000 

729 

20 

10 

30 

30 

20 

w 

416 

0 

222 

0 

10'- 

-6" 

405,000 

784 

20 

11 

31 

31 

20 

w 

426 

0 

235 

5 

10'- 

-9" 

423,000 

841 

20 

11 

32 

31 

20 


437 

0 

245 

7 

11'- 

-0" 

442,000 

841 

20 

12 

32 

32 

21 

w 

470 

0 

266 

0 

11'- 

-3" 

463,000 

900 

20 

12 

33 

32 

22 

V*' 

505 

0 

278 

9 

11'- 

-6" 

484,000 

961 

22 

11 

34 

33 

22 

w 

515 

0 

306 

5 

11'- 

-9" 

504,000 

961 

22 

12 

34 

34 

23 

V* 

550 

0 

326 

1 

12'- 

-0" 

524,000 

1024 

22 

12 

35 

34 

23 

w 

563 

0 

339 

7 


113 





































THE NATIONAL PRESSED STEEL COMPANY 


FOOTING TABLE 


1— D H 

! 


C 

-f“ 

B 

E 

1 

1 

J-^-*- 1 -*- J-! — i-1-*-J- 


i 

A—-* 



Soil Pressure 
6000 lbs. per sq. ft. 




Col. 

Load 

Minimum 

Area 





Round 
Bars Each 

Wt. 

of 

Volume 

A 


Base 

Plate 

Sq. In. 

B 

C 

D 

E 

No 

Way 

Size 

Steel 

Lbs. 

Concrete 
Cu. Ft.' 

3'- 

-0" 

53,000 

100 

9 

5 

13 

14 

8 

y? 

29. 

0 

9. 

1 

3'- 

-6" 

72,000 

144 

10 

5 

15 

15 

10 

a? 

43. 

0 

13. 

1 

4'- 

-0" 

94,000 

196 

11 

6 

17 

17 

11 

v* 

55. 

0 

19. 

2 

4'- 

-6" 

118,000 

256 

12 

6 

19 

18 

13 

a 9 

74. 

0 

25. 

9 

5'- 

-0" 

146,000 

289 

13 

7 

20 

20 

14 

y? 

89. 

0 

35. 

0 

5'- 

-3" 

160,000 

324 

14 

7 

21 

21 

15 

y*' 

100. 

0 

41. 

1 

5'- 

-6" 

176,000 

361 

14 

8 

22 

22 

16 

y* 

112. 

0 

46. 

5 

5'- 

-9" 

192,000 

400 

15 

8 

23 

23 

16 

y* 

118. 

0 

53. 

7 

6'- 

-0" 

208,000 

400 

16 

8 

23 

24 

17 

yt 

131. 

0 

61. 

3 

6'- 

-3" 

226,000 

441 

16 

9 

24 

25 

17 

W 

136. 

0 

68. 

3 

6'- 

-6" 

244,000 

484 

17 

9 

25 

26 

18 

w 

151. 

0 

77. 

5 

6'- 

-9" 

262,000 

529 

18 

9 

26 

27 

18 

y," 

157. 

0 

87. 

2 

V- 

-0" 

282,000 

576 

18 

10 

27 

28 

19 

A." 

171 

0 

96. 

0 

r- 

-3" 

302,000 

625 

19 

10 

28 

29 

19 

A" 

178 

0 

107. 

3 

V- 

-6" 

322,000 

625 

20 

10 

28 

30 

20 

A’' 

194 

0 

119 

4 

r- 

-9" 

344,000 

676 

20 

11 

29 

31 

21 

A." 

210 

0 

130 

3 

8'- 

-0" 

366,000 

729 

20 

11 

30 

31 

23 

l A" 

238 

0 

139 

0 

8'- 

-3" 

389,000 

784 

21 

11 

31 

32 

24 

A" 

256 

0 

153 

4 

8'- 

-6" 

412,000 

841 

22 

11 

32 

33 

25 

A/ 

276 

0 

169 

0 

8'- 

-9" 

435,000 

900 

22 

12 

33 

34 

26 

A 9 

296 

0 

182 

6 

9'- 

-0" 

461,000 

900 

23 

12 

33 

35 

28 

'A 9 

328 

0 

199 

9 

9'- 

-3" 

486,000 

961 

24 

12 

34 

36 

20 

W 

376 

0 

217 

8 

9'- 

-6" 

512,000 

1024 

24 

12 

35 

36 

21 

W 

406 

0 

230 

5 

9'- 

-9" 

539,000 

1089 

24 

13 

36 

37 

22 

W 

437 

0 

246 

4 

10'- 

-0" 

566,000 

1156 

25 

13 

37 

38 

22 

W 

449 

0 

267 

1 

10'- 

-3" 

594,000 

1225 

26 

13 

38 

39 

23 

%" 

480 

.0 

290 

1 

10'- 

-6" 

622,000 

1225 

26 

14 

38 

40 

24 

W 

514 

.0 

309 

.0 

10'- 

-9" 

650,000 

1296 

27 

14 

39 

41 

25 

y% 

547 

.0 

333 

.6 

11'- 

-0" 

681,000 

1369 

27 

14 

40 

41 

27 

w 

606 

.0 

349 

.2 

11'- 

-3" 

711,000 

1444 

28 

14 

41 

42 

28 

6 A 9 

644 

.0 

375 

.8 

11'- 

-6" 

744,000 

1521 

28 

15 

42 

43 

29 

As" 

681 

.0 

398 

.6 


114 
















































THE NATIONAL PRESSED STEEL COMPANY 


1 


FOOTING TABLE 



T 


C 

E 

1 

^,5* 

~T~ 

B 

1 


( 

--A-— 



Soil Pressure 
8000 lbs. per sq. ft. 


A 

Col. 

Load 

Minimum 
Area 
Base 
Plate 
Sq. In. 

B 

C 

D 

E 

Round 
Bars Each 
Way 

Wt. of 
Steel 
Lbs. 

Volume 
* of 
Concrete 
Cu. Ft. 

No. 

Size 

2'-6" 

49,000 

100 

8 

5 

13 

13 

8 

w 

24.0 

5.7 

3'-0" 

71,000 

144 

10 

5 

15 

15 

10 

A" 

37.0 

9.7 

3-6" 

96,000 

196 

11 

6 

17 

17 

11 

w 

48.0 

14.9 

4'-0" 

125,000 

256 

12 

7 

19 

19 

13 

A" 

65.0 

21.4 

4-3" 

141,000 

289 

13 

7 

20 

20 

14 

A" 

75.0 

25.6 

4'-6" 

158,000 

324 

14 

7 

21 

21 

14 

A" 

80.0 

30.4 

4'-9" 

176,000 

361 

14 

8 

22 

22 

15 

A" 

90.0 

35.1 

5'-0" 

195,000 

400 

15 

8 

23 

23 

16 

A" 

101.0 

40.9 

5-3" 

215,000 

441 

16 

8 

24 

24 

17 

A' r 

114.0 

47.3 

5'-6" 

236,000 

484 

16 

9 

25 

25 

17 

A'' 

119.0 

53.4 

5-9" 

257,000 

529 

17 

9 

26 

26 

18 

A" 

132.0 

61.2 

6'-0" 

279,000 

576 

18 

9 

27 

27 

19 

Ai' 

146.0 

69.4 

6-3" 

303,000 

625 

18 

10 

28 

28 

20 

Ai' 

160.0 

77.0 

6'-6" 

327,000 

676 

19 

10 

29 

29 

20 

A" 

167.0 

86.9 

6-9" 

352,000 

729 

20 

10 

30 

30 

21 

Ai' 

183.0 

97.5 

7'-0" 

378,000 

784 

20 

11 

31 

31 

22 

A " 

198.0 

107.3 

7'-3" 

405,000 

841 

21 

11 

32 

32 

23 

Ai' 

215.0 

119.5 

7'-6" 

434,000 

900 

22 

11 

33 

33 

23 

A!' 

223.0 

132.5 

7-9" 

462,000 

961 

22 

12 

34 

34 

24 

A" 

240.0 

144.0 

8-0" 

491,000 

1024 

23 

12 

35 

35 

25 

A n 

259.0 

159.2 

8'-3" 

522,000 

1089 

24 

12 

36 

36 

26 

A." 

278.0 

174.5 

8'-6" 

554,000 

1089 

25 

13 

36 

38 

26 

A" 

286.0 

194.0 

8'-9" 

586,000 

1156 

26 

13 

37 

39 

28 

A" 

318.0 

212.5 

9-0" 

619,000 

1225 

26 

14 

38 

40 

29 

A" 

339.0 

229.1 

9-3" 

652,000 

1296 

27 

14 

39 

41 

31 

A" 

373.0 

248.6 

9-6" 

689,000 

1369 

28 

14 

40 

42 

23 

A" 

445.0 

269.7 

9-9" 

724,000 

1444 

28 

15 

41 

43 

24 

A" 

476.0 

288.6 

lO'-O" 

760,000 

1521 

29 

15 

42 

44 

24 

A," 

487.0 312.3 


115 

















































THE NATIONAL PRESSED STEEL COMPANY 


COMPARISON OF DEAD WEIGHT IN FLOOR SLAB 
ITS EFFECT ON COST AND HEIGHT OF 

BUILDING 

Many interesting facts are developed by a parallel 
comparison between Steel Construction (Structural Steel 
Skeleton and Steel Lumber Floors) and Reinforced Con¬ 
crete Construction. The difference in the required height 
of building, weight and volume of material used, usable 
floor area in the finished buildings and length of time for 
construction are all important" factors. These points 
should all be analyzed and considered before the design 
of the structure is started. 

Steel Joist floors have a very low dead weight (35 to 
40 pounds per square foot) and thereby reduce the total 
load t© be carried by the beams. The loads supported by 
these members are reflected in the reduced size of steel 
columns, and further in the footings which carry the total 
load. 

In steel construction strength and stability are pro¬ 
vided by individual steel members of known quality. 
The high unit strength of steel results in comparatively 
small structural members. As compared with reinforced 
concrete, the floors and particularly the beams, are usually 
reduced in depth and the columns less in area. 

Referring to the floor slab sections shown on page 131, 
the concrete joist design using steel cores is the lightest 
weight concrete slab shown. This floor slab design has 
proven its efficiency and is in many parts of the country 
the most economical of any shown excepting steel joists. 

The development of the concrete joist design of floor 
slab was a big step in advance. Originally secured by the 
use of hollow tile it reduced dead load of slab and increased 
the length of economical span. The further development 
of the steel core increased the efficiency of the concrete 
joist floor slab, the basic efficiency of the design and the 
later increased efficiency by use of steel cores being entirely 
due to the resulting decrease in dead load. This reduction 
in dead load means saving of material to handle and re¬ 
duced cost in all supporting parts of the building. 

In principle this idea is carried further in the steel 
joist floor slab. Further reduction of weight is accom¬ 
plished by reverting back to a steel unit for all stress resist¬ 
ance, fire resistance being maintained by retention of the 
concrete slab above and plaster on steel lath ceiling below. 

To clearly demonstrate the difference in materials 
involved and one reason for the basic efficiency and 


116 







THE NATIONAL PRESSED STEEL COMPANY 


economy of steel joist floors, examine a floor slab design. 
Building area—100' x 200' with three rows of columns giv¬ 
ing slab span of approximately 24 feet. Live load 60 lbs. 
per sq.ft. Leave out the lath and plaster ceiling and wood 
floor finish, as they are the same in either case. Do not 
consider beams, columns and footings, although they only 
add to the saving in materials. 

CONCRETE JOIST FLOOR SLAB 
12" Steel Core—3" Concrete. 


Item Weight 

Reinforcing steel. 29,300 lbs. 

Steel cores. 35,500 

End caps. 1,200 

97 cu. yds. concrete (fill between screeds) 

463 “ “ “ (structural) 

615 cu. yds. gravel (10% waste). 1,700,000 

J2.7S “ “ sand (10% waste). 725,000 “ 

695 bbls. cement. 264,000 “ 

64,000 B. F. form lumber. 202,000 


Total. t . . . .2,957,000 lbs. 

Approximately 75 carloads of material. 

STEEL JOIST FLOOR SLAB 
Item Weight 

404 Pcs. 12" @ 12 lbs. joist.'. 119,300 lbs. 

103 cu. yds. concrete (fill between screeds) 

113 cu. yds. gravel (10% waste). 310,000 

48 “ “ sand (10% waste). 130,000 

110 bbls. cement. 41,800 

2220 sq. yds. steel lath. 8,900 


Total... . . 610,000 lbs. 


Approximately 15 carloads of material. 

On less than 20,000 sq ; ft. of floor area a total difference 
in weight of materials involved in the construction of 
the two slabs, which amounts to a saving of— 

2,347,000 pounds 
1,173 tons 

60 carloads. 

Sixty carloads of material that does not have to be 
transported, carted, hoisted, manhandled and supported 
in position during the life of the building. In one instance 
a floor slab involving the use of 1,479 tons of material to 
support a specified live load of d 70 tons. In the steel joist 


117 




















THE NATIONAL PRESSED STEEL COMPANY 


construction a slab weighing 305 tons to support the 
specified live load of 570 tons. 

Where storage space around a job is limited and where 
cartage haul is more than an average distance the question 
of volume and weight of materials assumes great import¬ 
ance. The importance of this reduced dead weight of 
floors is illustrated on page 119. This shows a typical 
column section designed for concrete construction and steel 
construction respectively, required for a building contain¬ 
ing six stories and basement having floor panels 20 ft. 
square and live loads as follows: First floor 125 lbs., 
second floor 100 lbs., upper floors 70 lbs., and roof 40 lbs. 
per square foot. The clear story heights were measured 
from top of finished floor to under side of projecting beam, 
thus establishing the total height of building in each 
construction. 

The weights given are for construction materials only 
(dead load) including items of finish as wood floors, plaster 
and fireproofing. 


Materials in one section 

Weight of floors and roof in¬ 
cluding beams (pounds)... 
Weight of columns. 


Concrete Steel 

356,000 138,000 

47,750 12,560 


Total weight on footing (pounds) 405,520 

Excavation for footing . . . .cu. yds. 10.00 
Volume of concrete in foot¬ 
ing._. # . “ “ 8.72 

Weight of reinforcing steel 

in footing.pounds 426 


150,560 
cu. yds. 2.53 

“ “ 2.02 

pounds 119 


The weights enumerated above represent only one 
section of the building as shown on drawings. The total 
saving will be this difference multiplied by the number 
of columns in the building. 

The cost saved due to decreased height of building 
exceeds the column and footing savings. In this example 
the height of building is reduced approximately 5%, 
resulting in a corresponding saving of that much brick 
work all around the building and the same per cent of 
partition materials, surfaces of wall and partitions to be 
plastered, length of piping, conduits and similar items. 

1 his example is worthy of very careful consideration. 
The same savings apply on practically every building 
operation. 


118 









Reinforced Concrete Construction 


1 


THE NATIONAL PRESSED STEEL COMPANY 


Comparative Design 



ce 

e 

o 


CO 

*■> 

A 

'CD 

is 

*3 

*■> 

o 


*-> 

a 

u> 

u 

C 

o 

U 



119 


Steel Construction 






































































































































































THE NATIONAL PRESSED STEEL COMPANY 


SPECIFICATIONS 

The following specifications have been developed for 
the purpose of aiding Architects in properly specifying 
Steel Lumber Construction and to aid Building Inspectors 
in drafting building code sections. The specifications 
can be used with absolute confidence either in whole or 
part as they represent the best thought and what is stand¬ 
ard practice at the present time. 

Description 

Steel Joist floor construction to consist of steel 
joists of proper size and weight for the spacing used wfith 
given loading and span. In no case shall steel joists be of 
lighter weight for given spacing than shown on plans. 
Joists are placed parallel to each other on supporting 
beams, partitions or walls, secured as show r n by detailed 
drawings and bridged at approximately the one-third 
span points or about 6 ' 0 " c-c with steel cross bridging. 

Over the joists a layer of painted 24 gauge diamond 
mesh rib lath is placed as a centering and reinforcing for 
the concrete slab. Under the joists the same kind of 
steel lath reinforces and supports the plaster ceiling. 

Steel Joists 

The steel joists to be made up of two symetrical channel 
sections placed back to back and securely spot welded 
together. The steel shall conform to the following re¬ 
quirements as to chemical composition: 

Phosphorus /Acid.not over 0.06 per cent 

(Basic. “ “ 0.04 “ “ 

Sulphur. “ “ 0.05 “ “ 

1 he thickness of steel to be not less than .072-inch 
(No. 15 Ga uge Birmingham). Flanges not to extend 
more than 2J^ inches from the web of the joist. All 
steel entering into the manufacture of these sections must 
show an ultimate tensile strength of not less than 64,000 
lbs. per sq. in. of section, and elongation percentage equal 
to 1,400,000 divided by the ultimate strength, and an 
elastic limit of not less than one-half the ultimate strength. 

Full facilities must be provided for the inspector to 
make, or have made, physical or chemical tests as in his 
judgment are necessary to determine the quality of 
material. 

All Steel Lumber sections shall be given a dipped coat 
of paint before shipment to destination. 


120 







THE NATIONAL PRESSED STEEL COMPANY 


Bridging 

Bridging shall be at least 1" wide, not less than No. 20 
gauge steel supplied in continuous lengths. Bridging to 
be secured to top and bottom of joists by 6d nails driven 
into the web. Single straps of not less than size and gauge 
above specified may be used. These straps shall extend 
from top flange of joist to the lower flange of adjoining 
joist. The straps must be drawn taut and fastened to the 
joists by bending the ends over flange and around and 
under secondary flange of joist. Rows of cross bridging 
should be placed at approximately the one-third points 
of span. 

Steel Lath 

Steel Lath shall be painted diamond mesh rib lath made 
from No. 24 Gauge steel and shall weigh not less than 4 
pounds per square yard. Ribs shall run parallel with 
length of sheet and occur at regular intervals of 4 inches 
across width of sheet. Lath shall always be applied with 
the long way of the sheet at right angles to joist. 

Floor Lath 

Floor Lath shall be placed on joists with ribs up and 
secured by means of spring clips about 12 inches on 
centers or by large headed roofing nails driven into web 
of joists. Ends of sheets shall lap directly over joists; 
sides shall lap by nesting ribs of adjoining sheets, floor 
lath shall not be placed until floor is ready to receive con¬ 
crete fill. 

Ceiling Lath 

Ceiling lath shall be applied with ribs up and in direct 
contact with joists. End laps shall occur under joists. 
Side laps shall be made by nesting ribs of adjoining sheets. 
Side laps shall be wired once at midway between supports. 
Lath shall be secured to the joists by means of spring 
clips spaced not over 8" on centers and applied in a manner 
to provide an even and rigid surface for plastering. 

Lath Clips 

Clips for fastening the steel lath shall be made from 
spring steel, so designed as to support lath over the full 
width of joist flange. 

Floor Filling 

The top lath is covered with floor filling as specified 
and shown on drawings and floor finish then applied. 


121 






1 


THE NATIONAL PRESSED STEEL COMPANY 


Nailing Strips 

Where wood floor finish is specified a 1 ^ x 1 screed or 
nailing strip shall be placed on top of the lath, parallel 
with and centering over the joists. This screed to be 
securely nailed to the web of the joists at frequent inter¬ 
vals with 16d nails. I he floor filling between screeds 
leveled off and lightly tamped slightly below their surface. 
Wood floor finish to be nailed directly to the screeds. 

Supporting Partitions 

Steel studs for supporting partitions shall consist of 
channel or I sections of sufficient strength to carry tlte 
load of floors to be supported. All connections shall be 
made with inch stove bolts or rivets. The steel lath 
shall be attached to studs with lath clips. 

Spacing 

In no case shall joists in floor construction, or any studs 
in bearing partition construction, be spaced more than 24" 
c-c. In roof construction where steel lath and a concrete 
slab are used above the steel joists, the joists shall not be 
spaced more than 30" c-c. Where steel joists are used to 
support cement tile on flat roofs spacing of the joists 
may be increased to meet the tile requirements, provided 
the joists are tied together at intervals not exceeding 
6'0" on center by a half inch round steel tie rod securely 
fastened through the joists at each end of the rods. The 
punching or holes for rod connections to be along the 
neutral axis of the joists. 

Bearings 

Where steel joists are supported by masonry walls, 
the joist shall have end bearing measured along the web 
of the joists equal at least to one-half the depth of the 
joists, and in no case less than 4". Where steel joists 
are supported by rolled structural sections, the bearing 
for all sizes of joists to be at least 2 Lj 

Steel joists supported by structural steel beams may 
be placed on top of the structural beams or on shelf 
angles riveted to webs of structural beams. The steel 
joists shall not be riveted or bolted to beams excepting 
under special conditions where standard details would 
not apply. Steel joists supported on top flanges of 
beams shall be fastened with clips designed for this 
purpose. Joists supported on shelf angles require no 
fastening. 


122 




THE NATIONAL PRESSED STEEL COMPANY 


Where necessary to make bolted or riveted connections 
between steel lumber sections or between steel lumber 
and rolled steel sections, use 3 ^" stove bolts or 3 ^" soft 
cold headed rivets. This to apply excepting where special 
conditions require other connections. In every instance 
standard practice applying to shear on rivets will govern 
each connection. 

Plaster Used with Steel Lumber 

All plaster used on ceilings and walls in connection 
with steel lumber sections shall be an accepted prepared 
plaster, prepared and mixed according to the manu¬ 
facturer’s instructions, or other plaster, but shall in 
any case have fire retarding qualities equal to cement 
plaster of the following proportions and mix: 

Cement Plaster: The first (scratch) coat shall con¬ 
sist of one part of Portland cement, one-tenth part of 
hydrated lime, one-tenth part of wood fibre and two and 
one-half parts of clean, sharp sand. All parts by volume, a 
sack of cement being countedas one cubic foot. All shall be 
mixed together dry until a uniform color and then water 
added to required consistency. Add sufficient long cattle 
hair or cocoanut fibre to bond mortar (about two pounds 
per bag of cement). Apply with considerable pressure, 
obtaining a good key and completely covering the steel 
lath, and then roughen the surface by scratching 
diagonally in both directions. 

The second (brown) coat to be of the same mixture 
with the hair omitted, and should be applied to the first 
coat after the latter has hardened sufficiently, but before it 
has become dry. 

Immediately before the application of the second coat, 
or any subsequent coat, the preceding coat to be well 
drenched with water applied with a brush or through a 
hose provided with a sprinkler nozzle. Bring second 
coat to a true and even surface within one-eighth inch to 
three-sixteenths inch of the face of the grounds. After 
this coat has been darbied and straightened in all direc¬ 
tions lightly scratch same with a scratcher. 

The finish coat to be one part Portland cement, one- 
tenth part of hydrated lime and two and one-half parts of 
clean, sharp sand. After the second coat has set firm and 
hard, but while still green (within twelve hours after wall 
has been browned out) apply a finish coat of the above 
mixture with a trowel and float it with a cork or carpet 
float to a true and even granular surface, using plenty 
of water in floating to secure an even surface. 


123 









THE NATIONAL PRESSED STEEL COMPANY 


Suspended Ceilings 

Suspended ceilings shall be constructed of rolled 
channels spaced 2'0‘' c-c and secured with No. 12 gauge 
wire to l}/^" rolled channels spaced 3'6" to 4'0" c-c, which 
in turn shall be suspended with " soft wire spaced 
3 '6" to 4'0" c-c secured by looping over joist above, 
before concrete has been placed. Apply same rib lath as 
specified heretofore to the channels with No. 16 gauge 
soft wire. 

Supporting Columns and Beams 

The Structural Steel skeleton frame which is an 
integral part of Steel Lumber Construction shall be pro¬ 
tected as follows: 

Beams 

Structural steel beams supporting Steel Joist floors 
shall be protected from high temperatures by extending 
the ceiling lath down the exposed sides of the beam below 
the bottom of the joists and under the beam. This lath 
to be securely fastened on a rigid frame work clipped to 
the beam. Plaster as above specified to be applied to 
this lath, adding extra coats to bring the total thickness 
to 1 Yi" or 2" as required. 

Columns 

Structural steel columns shall be protected from high 
temperatures by plastering on steel lath securely fastened 
to a frame clipped to the column section. Plaster to be 
applied in successive coats to required thickness of 1J4* 
or 2". 

Note —In every case the protection around structural 
steel columns and beams to be applied in such a manner 
as to provide an unbroken air space around the section. 


124 




THE NATIONAL PRESSED STEEL COMPANY 


FRAMING OPENINGS 


Steel Lumber Sections are used for framing only 
around the smaller openings as hot air pipes, ventilating 
flues, dumb-waiters and the like. Details as shown on 
page 80. For larger openings as stairwells, light shafts or 
skylights, where the framing members act as headers 
and trimmers, the resulting concentrated load is often 
heavier than can be economically carried on Steel Lumber 
sections. In such cases structural steel beams or channels 
are commonly used as framing members. Details as 
shown on page 81. Tables of carrying capacity of struc¬ 
tural sections for steel joist sizes are given on page 126. 
For concentrated loading conditions use formulas, pages 
158 and 159. 


Header and trimmer members should always be the 
same depth as the joists in order to preserve the flat ceiling 
and uniform thickness of floor. In first floor construction 
in some types of buildings, as in residences, an I section 
can be used as a column under framing points. This 
reduces the concentrated loading condition and often per¬ 
mits the use of Steel Lumber sections as framing members. 
Details page 146. Where architectural conditions show 
supporting partitions alongside of openings the framing 
can be handled as per details, page 147. 


In every case the determination of concentrated loads 
and required framing members is a straight designing 
problem. All framing members should be securely 
framed. The details of construction as shown in this 
handbook represent common practice. 


125 




THE NATIONAL PRESSED STEEL COMPANY 


FRAMING MEMBERS 

Safe Loads in Pounds Uniformly Distributed for 

Standard Structural I Beams. 

Safe Loads are Figured for Fibre Stress of 16,000 Pounds 
per Square Inch and Include Weight of Beam. 


Size 

4" 

5" 

6" 

7" 

i* 

8" 

9" 

10‘ 

12" 

Size 

Wt. 

7.7 

10.0 

12.5 

15.3 

18.4 

21.8 

25.4 1 

! 

31.8 

Weight 


6' 

5300 

8600 

12910 

18400 

25280 




6' v 



r 

4540 

7370 

11070 

15770 

21670 




V 



8' 

3980 

6450 

9680 

13800 

18960 

25160 



8' 



9' 

3530 

5730 

8610 

12270 

16850 

22370 



9' 



10' 

3180 

5160 

7750 

11040 

15170 

20130 

2605038370 

10' 



11' 

2890 

4690 

7040 

10040 

13790 

13300 

236803488011' 



12' 

2650 

4300 

6460 

9200 

12640 

16770 

217103197012' 



13' 

2450 

3970 

5960 

8490 

11670 

15480 

200402951013' 


<L> 

14' 

2270 

3680 

5530 

7890 

10830 

14380 

186102740014' 

+-> 

<v 

to 












c 

15' 

2120 

3440 

5160 

7360 

10110 

13420 

173602558015' 

c 

.*-) 

c 

a! 

a 

16' 

.... 

3220 

4840 

6900 

9480 

12580 

162802398016' 

e 

rt 

a 

V- 

aj 

17' 

.... 

3030 

4560 

6490 

8920 

11840 

153202257017' 

(f) 

U 

<L> 

u 

18' 



4300 

6130 

8430 

11180 

1447021310 18' 

6 

19' 



4080 

5810 

7980 

10590 

13710 70190 19' 

u 


20' 




5520 

7580 

10064 

130201918020' 



21' 




5260 

7220 

9590 

124001827021' 



22' 





6890 

9150 

1 1 840 1 7440 99' 



23' 





6590 

8750 

1132C 

16680 73' 



24' 






8390 

1085C 

1599024' 



25' 






8050 

1 f)47( 

■ 

) i 



26' 







1002014761 

) 26' 












— 


For safe loads below the heavy lines, the deflections 
will be greater than the allowable limit for plastered 
ceilings—1/360 of span. 


126 




































































THE NATIONAL PRESSED STEEL COMPANY 


FRAMING MEMBERS 

Safe Loads in Pounds Uniformly Distributed for 

Standard Structural Channels. 


Safe Loads Figured for Fibre Stress of 16,000 Pounds per 
Square Inch and Include Weight of Channel. 


Size 

4" 

5" 

6" 

7" 

8" 

9" 

10" 

12" 

Size 

Weight 

5.4 

6.7 

8.2 

9.8 

11.5 

13.4 

15.3 

20.7 

Weight 


6' 

3370 

5270 

7700 

10710 

14360 

18690 



6' 



7' 

2890 

4520 

6600 

9180 

12310 

10770 

16020 



7' 



8' 

2530 

3960 

5780 

8030 

14020 



8' 



9' 

2250 

3520 

5130 

7140 

9570 

12460 



9' 



10' 

2020 

3160 

4620 

6430 

8610 

11220 

14270 

22780 

10' 



IP 

1840 

2880 

4200 

5840 

7830 

10200 

12970 

20700 

IP 



12' 

1690 

2640 

3850 

5360 

7180 

9350 

11890 

18980 

12' 



13' 

1560 

2430 

3550 

4940 

6630 

8630 

10980 

17520 

13' 

4 -> 

<& 

<v 

14' 

1440 

2260 

3300 

4590 

6150 

8010 

10190 

16270 

14' 

(V 

<V 

£ 

15' 

1350 

2110 

3080 

4280 

5740 

7480 

9510 

15180 

15' 

.5 

c 

s 

rt 

a 

16' 

.... 

1980 

2890 

4020 

5380 

7010 

8920 

14230 

16' 

rt 

a 

CO 

u 

d 

17' 


1860 

2720 

3780 

5070 

6600 

8390 

13400 

17' 

U 

d 

0) 

u 

18' 



2570 

3570 

4790 

6230 

7930 

12650 

18' 

b 


19' 



2430 

3380 

4530 

5900 

7510 

11990 

19' 



20' 



3210 

4310 

5610 

7130 

11390 

20' 



21' 




3060 

4100 

5340 

6790 

10850 

21' 



22' 




3920 

5100 

6490 

10350 

22' 



23' 





3750 

4880 

6200 

9900 

23' 



24' 






4670 

5940 

9490 

24' 



25' 






4490 

5710 

9110 

25' 



26' 







5490 

8760 

26' 



For safe loads below the heavy lines, the deflections 
will be greater than the allowable limit for plastered 
ceilings—1/360 of span. 


127 

































































THE NATIONAL PRESSED STEEL COMPANY 


Garage Floors 

In garage construction the floors offer special problems, 
particularly in view of the uncertainty of future develop¬ 
ments in the Automotive industry. The questions arising 
in this class of buildings revolve around the application of 
concentrated loads. In steel joist floor construction this 
necessitates special consideration of the concrete slab over 
the joists and spanning between them. Experience has 
shown that when the joists are spaced 16" on centers that 
2" of concrete on steel lath will support all concentrated 
loads which happen to apply between joists. 

In analyzing the slab this efficiency is hard to verify'by 
theoretical designing. This for two reasons:—first, The 
slab is so perfectly reinforced by the expanded metal (steel 
lath) that higher loading values are secured than safe 
designing principles as applied to ordinary concrete work 
will theoretically develop. Second, The loads as applied 
on garage floors are not actually concentrated loads when 
the short net length of the slab span is considered. This 
span in most cases does not exceed twelve inches between 
joist flanges. Truck wheels are now designed so that the 
bearing area increases with the loading capacity. A load 
is not applied along a line but is applied over an area of 
some width and length. It is more nearly a uniform load¬ 
ing than a concentrated loading as far as the concrete 
slab over the joists is concerned. 

The large open area in garages makes it advisable that 
attention be given to proper provision against cracking 
from expansion and contraction. The floor should be 
divided into panels by expansion joints or reinforced with 
temperature reinforcing bars. 

Satisfactory results will always be secured on 
garage floors by spacing the joists 16" c-c laying a concrete 
slab on top of the floor lath with a finished thickness of 
two and one half inches and cutting expansion joints about 
twelve feet on centers each way. 

In designing floors always give attention to that factor 
which because of the intended occupancy assumes rela¬ 
tively the greatest importance. In garage floors for 
instance the strength of the concrete slab between joists 
to support concentrations of loading. On the other 
hand if designing a dance hall floor the question of rigidity 
is more important. In such case it is better to use a deeper 
joist on a wider spacing. The greater joist depth giving 
greater rigidity. 


128 




THE NATIONAL PRESSED STEEL COMPANY 


STRENGTH OF SLAB ON JOISTS 



When floors are finished in concrete, tile or the like, the 
concrete slab over the joists carries the floor loads between 
joists. These loads may be concentrated as in case of 
partitions or heavy safes. The table below gives the safe 
uniform square foot loading and safe concentrated load¬ 
ings applied between the joists. This table does not take 
into consideration the reinforcement value of bars that 
may be used as temperature reinforcement although such 
bars add considerable to the transverse strength of the 
concrete slab on top of Steel Joists. 

TOTAL SAFE LOADS 

W = Load per Square Foot. Uniformly Distributed. 

P=Load Concentrated at Center of Span. 


Thickness 
of Slab “d" 

Area of Steel 
per Foot of 
Width of Slab 

SPAN “b” 

12" 

16" 

19" 

24" 

W 

P 

W 

P 

W 

P 

W 

P 

2" 

2 Vi" 
3" 

. 135 
.135 
. 135 

2136 

2700 

3240 

1600 

2025 

2430 

1606 

2025 

2436 

1200 

1522 

1827 

1285 

1626 

1950 

1012 

1281 

1538 

800 

1012 

1215 

800 

1012 

1215 


Unit Working Stresses: 

Concrete in Compression not over 550 lbs., per square inch. 
Tension in Steel not over 16,000 lbs., per square inch. 

Unit Shear not over 50 lbs., per square inch. 


129 












































THE NATIONAL PRESSED STEEL COMPANY 


Weight of National Steel Lumber Floors 

The dead weight of floor construction will vary accord¬ 
ing to the nature of materials used for floor finish. Below 
is given the average weight of standard Steel Lumber 
floor having wood floor finish applied directly to wood 
nailing strips— 

Weight per 
sq. ft. 


Wood Flooring. 3 lbs. 

1% inches Concrete. 21 lbs. 

Steel Joists and Bridging (Average). 4 ibs. 

Plaster Ceiling and Lath. 8 lbs. 


Total. 36 lbs. 


In determining the average weight of steel joists a 
nine inch section spaced 24 inches on centers was assumed. 

Cement, Terrazo or Tile floor finishes increase the 
dead weight of floor to some extent. Usually the total 
thickness over joists, including the concrete fill and 
finish, averages 2p2 inches, which would increase the total 
weight of floor construction, after first deducting weight 
of wood flooring, to 42 lbs. per square foot. 

Proper correction in the above table should be made 
according to size and spacing of joists and nature of floor 
finish required in the design. 

Forty pounds can be safely assumed as the dead load 
per square foot of finished Steel Joist floor construction. 
A difference of a few pounds per square foot over an 
extended floor area is of sufficient importance to warrant 
actual computation of dead load in every instance. 

The floor sections shown on page 131 constitute the 
more popular types of floor construction. Note the design 
of each slab. Consider the various factors involved. 
The strength of the steel joist floor is confined to a section 
made under conditions permitting of positive inspection 
and resulting in known uniformity. The fire protection 
is scientific, practical and utilizes the more dependable 
merits of the materials involved. The Steel Joist floor is 
equally as meritorious in every respect as any other type 
of floor construction ever devised. A comparison of weight, 
efficiency, merit and cost recommends Steel Joist Floor 
Construction for favorable consideration. 

I_ 


130 










THE NATIONAL PRESSED STEEL COMPANY 


COMPARISON OF WEIGHT PER SPUARE FOOT 
VARIOUS FIREPROOF FLOOR CONSTRUCTIONS 
WORKED OUT FOR SAME LOADING AND SPAN 




WEIGHT 


PER 

s<3. poot 

40 LBS. 


(WOOD NAILING BLOCK5 r WOOD FLOOR 


STEEL JOIST CONSTRUCTION) 





— 


■4 


, » 

• J>* . ** .A. A . A * e> .' ’ s •» •’.** • t>. •** *. • O .. A • ' • A 

/> *.L •• a. . a* ^ 

- 

P 

r 

• 


CONCRETE SLAB - PLATE REINFORCEMENT 



CONCRETE JOIST-HOLLOW TILE 


86 LBS. 


102 LBS. 



REINFORCED CONCRETE SLAB 


131 












































































































THE NATIONAL PRESSED STEEL COMPANY 


GENERAL INFORMATION 
Billet or Slab. 

A billet is a semi-finished steel product reduced in a 
blooming mill from an ingot. A billet may be in various 
shapes but the term is usually applied to a square section, 
the corners of which are rounded. When the section is 
rolled in the shape of a rectangle it is called a slab. Billet 
bars are rolled in long lengths, depending upon the sec¬ 
tion and upon the size of ingot. The billet is then sheared 
to the length desired. The billet bar receives the same 
heat treatment and working as an I Beam. 

Strips. 

A strip is a long narrow piece of steel ranging in thick¬ 
ness from approximately to and is rolled out from 
a billet or slab. The term strip generally applies to widths 
from 4" to 24", and they are usually produced on con¬ 
tinuous rolls. The length of strip is from 90 to 130 feet. 
National Strip Production. 

National Strip Steel is produced from billets or slabs 
which have been heated to approximately 2100° F. in a 
continuous furnace. The advantages of a continuous fur¬ 
nace for heating slabs is very important. As the slab 
goes through the furnace the temperature gradually in¬ 
creases. Instead of a quick burning heat being applied 
and scaling the outside of the slab a slow soaking heat is 
obtained. It takes about 3 hours for the slab to travel 
the 62 feet through our furnaces. The discharge temper¬ 
ature is a little over 2100° F. The slab comes out thorough¬ 
ly soaked. These slabs are then passed through a uni¬ 
versal mill which rolls the material in both directions, 
giving a kneading action, which greatly refines the fibre of 
the steel. This results in a steel much softer and easier 
to work than that produced by the continuous rolling 
process. In view of the large reduction and the long 
length of strips, the material cools off very rapidly and 
the process of reduction necessarily must be rapid. 
The strips are handled on an automatic electrically 
driven table and the rolls are all run at high speed. It 
is necessary that the reduction be accomplished before 
the material has cooled below the lower recolesence point 
and for that reason the finished temperature of National 
Strips is approximately 1300° F. If the strips cool 
below this point the rolls will not take hold and it is 
impossible to secure the desired gauges. The effect of 
this high temperature finish is that the material is abso¬ 
lutely free of internal stresses, being in exactly the same 


182 




THE NATIONAL PRESSED STEEL COMPANY 


condition as an annealed sheet with the exception that 
there has been no reduction in ultimate strength, as is the 
case with an annealed material. 

Coils. 

After the strip has been reduced to its proper width 
and gauge it is coiled to facilitate handling. These coils 
are then carried to the stock pile. From the stock pile 
it is handled to the forming machines. At the forming 
machine the coil is placed on a spindle, one end of the strip 
introduced into the forming mill and the strip automatical¬ 
ly uncoiled as it travels through this machine. 

Forming Mill. 

The forming mill rolls the strip into a channel 
section, see sketch. This operation is performed by a 
series of rolls which gradually form up the desired shape. 
As the strip enters the forming mill it passes between rolls 
that run in oil. The main purpose of this oiling process is 
to facilitate production. It also serves to oil the backs of 
the channels, preventing any chance for corrosion in the 
seam of the I joist. Every step in the production of Steel 
Lumber is a rolling process. The channel sections come 
from the forming mill in lengths from 90 to 130 feet long. 



I Joist Welding. 

After the steel lumber channels are formed they are 
sorted for length. Two channel sections are placed back 
to back, and in this position are passed through an electric 
spot welding machine which spot welds the webs together. 
The location of these welds is as shown above. 


133 

























THE NATIONAL PRESSED STEEL COMPANY 


These welds are in diameter. The entire 
elimination of the human equation results in absolute 
uniformity. The amount and time of current and pressure 
applied being constant the welds will not break. Tested 
to destruction a disc is torn out of one of the plates. 

Cutting. 

A friction type of saw is most suitable for cutting steel 
joists to desired lengths. This type of saw is designed so 
that bevel cuts can be made equally as well as straight 
cuts. 

Painting National Sections. 

Before Steel Lumber sections are shipped they are dipped 
in a special asphalt base paint. The method used in dip¬ 
ping the section is to place the joists in neat piles conven¬ 
ient for handling. These piles are then picked up by crane 
and dipped into a large paint vat. A suction pump forces 
the paint through the joist stacks insuring complete cover¬ 
ing of entire surfaces of all sections. They are then placed 
on a drying rack for about two hours before loading, 
then loaded into cars. 

Steel Lumber sections are painted to protect them from 
corrosion during transportation and the installation period. 
After they are in place in the building and the building is 
completed, conditions that cause corrosion do not exist 
and the painting is then unnecessary, but during the 
erection period they are generally stored out in the open 
and in order to'afford protection during this period it is 
advisable to have them well painted at the mill. 

Nature of Steel used in National Steel Lumber 

Sections. 

In National Steel Lumber Sections the steel used is of 
standard analysis of a carbon content from .16 to .24. 
Phosphorus and Sulphur are held under .04, and Man¬ 
ganese under .35. This relatively high carbon content, 
together with th.e method of working the material, gives 
a uniformly high ultimate strength. National Steel 
Lumber Sections will show a uniform average ultimate 
strength exceeding 72,000 lbs. per sq. in. 

Types of Buildings to which Steel Lumber Construc¬ 
tion is more Particularly Adapted. 

Steel Lumber construction is efficient from a structural 
point of view for any class of building. Ordinarily it 


134 




THE NATIONAL PRESSED STEEL COMPANY 


is more particularly applicable to those buildings where 
the live loadings are less than 150 lbs. per sq. ft. On 
account of the lack of dead weight and inertia it is not 
a desirable floor construction for heavy factory buildings 
with vibratory loads. This does not apply, however, for 
light factory buildings with loadings from 125 to 150 lbs. 
per sq. ft. The efficiency and basic merit of Steel Lumber 
construction is more apparent in such buildings as hotels, 
office buildings, apartment houses, hospitals, garages, 
schools, residences and the like. 


Principal Advantages of Steel Lumber Construction. 

The principal advantages of Steel Lumber Construction 
are its fireproof qualities, sound-proof qualities, durability, 
economy, adaptability, rigidity, low dead weight, simpli¬ 
city of design, ease and rapidity of installation and sanitary 
qualities. 


Fireproof Quality. 

To start w ? ith the elimination of combustible materials 
in a building always decreases the fire hazard. Secondly, 
Steel Lumber sections being absolutely free from all internal 
stresses will not twist or distort under high temperatures 
as do ordinary structural steel sections. In common with 
all low carbon steels the material from which steel joists 
are made reaches its maximum strength under compara¬ 
tively high temperatures. In fact, National Steel Joists 
will carry their greatest loads at around 700° F. With 
plaster on steel lath ceiling applied underneath the joists 
higher fire temperatures underneath the floor slab will 
not develop temperatures exceeding 500° F. between the 
joists. Conservatively speaking at least 90% of the 
fires in buildings do not develop temperatures exceeding 
1200° F., and under these temperatures without any 
ceiling plaster protection there will be no detrimental 
effect on the joists. Graph page 6. One and one-half 
to two inches of concrete on steel lath above the joists 
furnishes an ample fire block to prevent the spreading of 
the fire from one floor to another. It is, of course, imper¬ 
ative that in all first class fireproof buildings that plaster 
on steel lath be applied to ceilings and that the columns 
and beams supporting the steel lumber be properly 
protected. 


135 




THE NATIONAL PRESSED STEEL COMPANY 


Sound Proof Qualities. 

In the study of the transmission of sound it is first 
necessary to recognize that sound is vibration, and it 
may be transmitted in buildings either by molecular 
vibration or by what is termed body vibration. Given 
any one continuous material a vibration will be trans¬ 
mitted more readily than it will through a series of ma¬ 
terials with different densities. In Steel Lumber construc¬ 
tion the sound in order to pass through a given floor or 
partition must pass through first a layer of concrete, then 
either the steel joists or the air space, then through a layer 
of plaster. The densities of all these materials are widely 
different. The result is that it is very difficult to transmit 
any sound whatever through a Steel Lumber floor or parti¬ 
tion. As to body vibration or what would entail the vibra¬ 
ting of an entire floor or partition, the rigidity of the con¬ 
struction precludes the possibility of transmitting sound 
in this manner. There is practically no information upon 
the actual relative sound-proof qualities of various build¬ 
ing materials, and the only manner in which this can be 
checked up at present is by actual observation of existing 
buildings. The question of design and construction 
enters so prominently into the efficiency of any building 
as to sound-proof qualities that the relative merit of ma¬ 
terials used is of only relative importance. It is a well 
known fact attested to by hundreds of owners that a Steel 
Lumber building gives absolute satisfaction on this point. 

Durability. 

In designing a fire-proof permanent building it is the 
endeavor of all concerned to construct a building which 
will have the smallest possible depreciation over the 
longest term of years. The elements start to cause depre¬ 
ciation as soon as the building is completed, and this 
depreciation eventually shows up in many ways. Steel 
is a known material and its durability and permanence 
under given conditions are established as a result of past 
experiences. It is known that in buildings there is no 
opportunity for corrosion of steel excepting for those 
conditions which may be introduced locally, such as a leaky 
steam pipe or water pipe. Any such condition is always 
evidenced immediately under the ceiling plaster and ample 
opportunity given for correction long before any detri¬ 
mental results have taken place on the steel structural 
members—such local conditions occurring very rarely 
offer no problem for consideration in connection with the 
durability of steel in building construction. The condition 


• 136 




THE NATIONAL PRESSED STEEL COMPANY 


of ceilings, walls and floors as to cracking, etc., is one of 
the principal features of a Steel Lumber building. All 
plastered surfaces being mechanically bonded to and rein¬ 
forced by steel lath give the most highly satisfactory 
results. Large areas of concrete floors under the hardest 
usage will stand up with surprisingly little depreciation. 
In other words, the general appearance of a building after 
years of usage is the concrete evidence of the durability 
of the type of construction used. An examination of 
Steel Lumber structures in comparison with buildings of 
other types of construction of equal age emphasizes the 
desirable qualities inherent to the use of this material. 
Corrosion. 

In order for corrosion to start or continue on steel, 
moisture and oxygen must be supplied. In buildings the 
moisture, except from local conditions, must be supplied 
from the atmosphere. This necessitates condensation 
which requires a difference in temperature between the 
steel and the surrounding air. As the temperature around 
the steel is the same at all times this condition cannot 
exist and corrosion cannot follow. 

With structural steel columns and beams protected 
with steel lath and plaster supporting the standard steel 
joist floor construction the structure will never deteriorate 
because of corrosion. This applies regardless of the loca¬ 
tion or relative humidity. 

Economy. 

The relative economy of any construction is directly 
dependent on the cost of materials, efficiency of labor, 
time consumed in erection, cartage and handling. 

The materials involved in Steel Lumber construction 
are not cheap. Concrete is of course relatively the same as 
in any other type of design. Steel Lath is a high class 
material involving an expensive manufacturing process. 
Steel Joists are more expensive per pound than reinforcing 
bars or rolled I beams. This directly resulting from a 
necessarily more expensive production process. However 
the combination of these materials in such a manner as to 
take advantage of the merits of each gives a most economi¬ 
cal result. Comparing the cost of all the materials in¬ 
volved in steel joist floors with those of other designs will 
usually show a favorable saving. The dead weight of 
a finished steel joist floor slab is approximately thirty- 
eight (38) pounds per sq. ft. This weight is only one-third 
to one-half of other equally efficient designs. This reduc¬ 
tion in weight materially reduces the size of main carrying 
girders and supporting columns, making a saving in 


137 




THE NATIONAL PRESSED STEEL COMPANY 


materials involved in the entire skeleton frame and all 
footings. To secure the full benefit of the possible sav¬ 
ings in materials a careful analysis should be made of 
every structural portion of the building. 

The efficiency of labor on an operation does not 
necessarily mean the actual degree of application of each 
individual. More important is the opportunity for effi¬ 
ciently applying the labor so as to more quickly gain 
the desired end. Compare the simplicity of steel con¬ 
struction with others. The usual muss and clutter, maze 
of temporary timbers, huge piles of sand and gravel and 
the like are conspicuous by their absence. In place of 
every appearance of confusion there is a prevailing incen¬ 
tive to simple efficiency. The various crafts have oppor¬ 
tunity to take up their work in natural order and to 
continuously prosecute their work without delay. Every 
step, every operation in the construction of a Structural 
Steel and Steel Lumber building is so much definitely 
accomplished. No part is put in place temporarily and 
later entailing the work of tearing out. Even the necessary 
attention of the designing Architect or Engineer, the 
inspection of the work, is greatly decreased and at the same 
time made more positive. 

The owner of a building is ordinarily anxious for 
completion. From the time work is first started the opera¬ 
tion involves an investment. On this investment no 
returns can be realized until the building is turned over 
for possession. In many instances this item involves a 
considerable sum per month, and any reduction in time of 
erection results in a direct saving to be credited to con¬ 
struction cost. Because of the simplicity of construction 
and the opportunity for all trades to operate continuously, 
the saving in erection time effected by the use of Steel 
construction, compared with other equally efficient de¬ 
signs, is from twenty to thirty per cent. The season of the 
year has a decided effect on the cost of any construction 
work but this effect is considerably less on steel installa¬ 
tions. Structural Steel and Steel Lumber can be erected 
in the winter time with nearly the same efficiency as in 
the other seasons. 

The cost of cartage and handling are directly in propor¬ 
tion to volume weight and bulk of materials used. A 
construction saving from fifty to sixty-five per cent on 
weight and bulk certainly effects a big saving. The longer 
this cartage distance and the higher the building the greater 
the economy of steel designs. 


138 




THE NATIONAL PRESSED STEEL COMPANY 


Adaptability. 

Steel Lumber Sections are adaptable to all kinds of 
buildings regardless of where they may be located. The 
cost per sq. ft. of installing Steel Lumber floors in a small 
building is no more than the cost of installing in a large 
building. Also the location of a building, whether in a 
city or in the country, does not effect the installation cost. 
In other words, the construction is equally applicable to 
large and small buildings regardless of their location. 
This for the reason that no special equipment is necessary 
for erection and either common or skilled labor can be used 
to advantage. 

Rigidity. 

Any floor construction to give satisfactory results over 
a long period of years must be rigid enough to stand up 
under all designed loading conditions with a minimum of 
deflection. A common principle in design is that the depth 
of beam in inches should be at least one-half the net span 
in feet. This regardless of the shape or width of section. 
In any construction wherein the structural sections in the 
floor slab run under this requirement there must be an 
allowance in the designed stresses or eventually the error 
will show up in a deterioration of floors and ceilings. 
Steel Lumber Sections are so designed as to meet all re¬ 
quirements of rigidity, and the material itself, due to its 
high elastic limit, gives a minimum of deflection under any 
. given loading and will resume its normal position under 
excessive deflections. Results of this inherent quality 
in the material are apparent in those buildings constructed 
many years ago, the ceilings and floors of which are today 
in the very best of condition. 

Dead Weight. 

What is known as dead load or the weight of the con¬ 
struction itself constitutes volume and weight of material 
which has to be supported and held in place in addition to 
any live loadings which are contemplated and will be super¬ 
imposed on the slabs. The efficiency of using a floor slab 
weighing not to exceed more than 40 lbs. per sq. ft. to 
carry a live load of 80 lbs. as compared with a floor slab 
weighing 100 lbs. per sq. ft. to carry the same live load can 
be readily appreciated. In addition every pound that can 
be saved in the weight of floor construction reduces the 
load on supporting beams, columns and footings. It also 
means that much less material has to be transported, 
carted, hoisted and manhandled. The handling of less 

I--- 


139 




THE NATIONAL PRESSED STEEL COMPANY 


material expedites the construction of a building, which 
further results in greater economy. 

Refer also to pages 116 to 119 where data on compari- 
tive weights is given. 

Simplicity. 

Any structural unit which is self contained is mu ch 
simpler in design than one which has to be built up of a 
number of materials during the course of erection. Also 
the adaption of steel joists to any other floor construction 
is very similar to the adaption of wood joists and offers a 
minimum problem in framing and taking care of various 
small openings. Further, the knowledge that the material 
will positively give the results desired eliminates the neces¬ 
sity of providing for the large unknown factors existing in 
any type of construction which entails a combination of 
materials for structural purposes. 

Installation. 

The installation of steel joists involves practically 
the same operations as the installation of wood joists. 
The preparation of steel joists for the job is done at 
the fabricating plant, and they are delivered ready to 
place in position. The application of lath to steel joists is 
much more rapid than is the application of wood lath to 
wood joists. The ease of installation is apparent and one 
of those qualities most quickly recognized by contractors. 
Page 55. 

Comparison with Wood Construction. 

The comparative cost of steel joist and wood joist con¬ 
struction depends very largely on the type of floor finish 
used in each case. A careful consideration of this item 
will often result in the adoption of fire safe construction 
at practically the same cost as wood construction. Con¬ 
sidering the superior merits, i. e., fire safeness, sound proof¬ 
ness, sanitary conditions, elimination of rodents, elimina¬ 
tion of plaster cracks, rigidity and so on, the investment of 
a considerable extra sum only represents true economy. 
The resulting sense of satisfaction and security is worth a 
real investment. The way to eliminate fire losses is not 
by continuing to pay insurance premiums but to build 
fires out of buildings. Wood as a structural material 
represents the pioneer stage in this country. Certainly 
for the purpose and the time it had no equal; this because 
of its adaptability and universal availability. We are now 
past the stage of pioneer building. This country in no 
part can long afford to continue building of flimsy, inflam¬ 
mable materials. 


140 




THE NATIONAL PRESSED STEEL COMPANY 


Fire Safe First Floors. 

A step in the right direction is to at least build in fire 
safe first floors. This can be done without increasing 
the cost of other portions of the building. Usually the 
foundations provided for a wood structure are sufficient 
for supporting a Steel Joist first floor. The balance of the 
building can be put up in wood. As the greater fire risk 
in the ordinary building is in the basement a large measure 
of absolute protection is afforded by fireproofing the first 
floor. In addition the elimination of shrinkage which 
invariably occurs in wood members results in a reduction 
if not entire elimination of all plaster cracks. The lower 
depreciation rate and increased value of the structure 
offset the small additional cost. 

Supports. 

Steel Lumber floor construction can be supported on 
brick, concrete, tile or any kind of masonry walls, also 
structural steel I beams, channels, built up girders and 
reinforced concrete beams. When steel joists bear on 
masonry walls the joists should have a bearing equal to 
one-half the depth of the joist, and never less than 4" 
measured along length of joist. It is well to slush cement 
mortar around joists when they are imbedded in brick 
walls. This to prevent moisture creeping through along 
the joist and to insure a tight wall, see page 87. In con¬ 
nection with structural steel members the joists may be 
supported directly on top of beams, being held in place by 
Beam Clips which fasten around the upper flange of the 
rolled beam and the lower flange of the steel joist, page 36. 
When carried on top of a supporting beam the joists may 
be either butted or lapped. Where the joists lap it is un¬ 
necessary to use a beam clip but instead they are tied to¬ 
gether by nailing a strip of bridging across the top of 
joists into the web directly over bearing, see page 85. A 
very common method of supporting joists is on shelf angles 
riveted to the web of supporting beams. This is a desirable 
method where it is necessary to save in head room. The 
shelf angles should be not less than 3 x 2 Yi x l /i" and in 
all cases the 3" leg of the angle should form the bearing for 
the steel joist. The angles should be located so that top 
of steel lumber joists can be placed under the top flange 
of structural steel I beam, allowing for a slight clearance. 
Refer to tables on page 90. Steel joists can be framed 
flush with top of structural steel members but by so doing 
it is necessary to cope off the top flanges of the joists at 
the ends, see page 87. This entails extra fabrication and 


141 








THE NATIONAL PRESSED STEEL COMPANY 


'ncreases the cost of the construction without in most cases 
any particular benefit. 

Where steel joists bear on structural steel beams they 
should have at least 2" bearing. Where the flanges of the 
beams are not wide enough to permit this bearing the joist 
ends should be lapped, see page 85. 

Joist Spacing. 

The standard spacings for steel floor joists are 12"> 
16", 19" and 24". The maximum spacing of floor joists 
when used in garages, factory buildings, warehouses, or 
buildings of this type more or less heavily loaded, should 
not be greater than 16" on centers. Tables page 129. 
For hotels, school houses, apartments, hospitals, residences, 
office buildings, or other buildings of similar character, 
24" centering of joists as a maximum gives satisfactory 
results. In roof construction it is permissible on account of 
the absolute uniform loading applied to increase the 
spacing of joists to 30". The reason for the particular 
spacings above noted is on account of the standard length 
of steel lath sheets, which is 96". 

Erection of Steel Lumber. 

The installation of steel joist and accessory materials 
is very simple. See page 55. The operations are very 
similar to those followed in erecting wood joist floors. 
After the bearings have been prepared the joists are placed 
in position. Temporary wood strips are placed on top of 
and at right angles to the joists and nailed in position. 
These strips should be placed near each end of the joists 
and approximately at each line of bridging. These strips 
hold the joists true to spacing, keep them in an upright 
position and materially aid in the proper installation of 
the building. These strips to be taken up just prior to 
the placing of the floor lath. 

Heating, Plumbing Pipes and Conduits. 

After the bridging has been placed all pipes should be 
installed. Pipes may be hung between or under the joists 
by means of strap pipe hangers. Methods of handling 
pipes are illustrated on pages 93 to 95. Where wood 
floor finish is to be applied small pipes and electric conduits 
may be placed on top of joists above the lath, but where a 
concrete or tile finish is to be applied all such pipes should 
be laid before the floor lath is applied. This provides for 
the reinforcing of concrete over the pipes and prevents 
cracking. Page 78. 


142 




THE NATIONAL PRESSED STEEL COMPANY 


Steel Lath Installation. 

Steel lath is laid with the long way of the sheet at right 
angles to the joist. The lath should be given proper side 
laps. The side lap not less than Yl inch if the ordinary 
flat Diamond Mesh Lath is used. With a rib lath the 
side lap is taken care of by nesting the side ribs. It is 
advisable on wider spacings to wire these side laps at least 
once at center between each row of joists. The lath is 
secured to the top flanges of the steel joist by the use of 
large headed roofing nails or spring lath clips. These 
should be spaced about 12" on centers. Refer to pages 
44 to 48. In case pipes are hung below bottom of joists 
as shown on page 95, it is necessary to use a suspended 
ceiling to cover them. In this case round rods are 
dropped down from the joists, one of the ends of the rod 
hooking over the top flange of the joists. These rods 
should be spaced every 3'6" to 4'0" along the length of 
the joists and 3'6" to 4'0" centers in the opposite direction. 
In applying lath to suspended ceiling frame work it is wired 
in place. Where applied directly to the bottom flanges of 
the joists it is fastened by spring lath clips which rigidly 
and positively hold the lath in place. 

Wood Nailing Strips. 

The wood nailing strips are applied directly on top 
of the steel lath over the joists. These nailing strips are 
x l%" continuous wood strips and are laid parallel 
with and on top of joists and securely nailed to the joists 
with a 16d nail. Nails should be spaced 18 to 20" on center 
and the strip cut around any pipes or conduits running at 
right angles to the joists. See page 94. 

By nailing the strips directly to the joists a positive 
connection is formed which precludes the possibility of 
nailing strip loosening up and causing squeaking floors. 
This is a particularly desirable point in Steel Lumber con¬ 
struction as compared with constructions where the nailing 
screed is simply embedded in concrete and held in place 
by that material. 

Concrete Fill. 

After the nailing strips are in place the concrete fill 
is put on top of lath in between the strips. The concrete 
is spread so that the fill, when tamped, will be about A" 
below top of nailing strip. Where a wood finished floor 
is used the concrete fill can be a comparatively inexpensive 
mixture as it acts entirely as a fire block. The concrete 
must not be mixed wet enough to run through the lath, 
but should be sufficiently plastic to allow a good bond with 


143 




----- 1 

THE NATIONAL PRESSED STEEL COMPANY 



the lath. In case a concrete, tile, marble or terrazo finish 
floor is desired, the wood nailing strips are eliminated. The 
mixture of concrete essential for this type of construction 
must be the standard mixture as used in any good floor 
slab work. The application of the finished surface is 
installed in the usual manner. Refer to page 77. There 
are preparations on the market which take the place of 
concrete and in which nails can be readily driven. The use 
of some of these materials is often practical, taking the 
place of the concrete and nailing strips. Wood flooring 
then being nailed directly to the filler. 

Spring Lath Clips. 

Spring lath clips are made from the very highest grade 
of spring steel and are simple and easy to apply. The 
principal advantage in using the spring lath clip for 
ceiling work is to eliminate the old fashioned prongs which 
were punched in the bottom flanges of the Steel Lumber 
joists. These prongs made the handling of the joists very 
unhandy and in a great many cases they were broken off 
while being shipped and installed on the job. In addition, 
the prongs only held the lath at one point while the clips 
hold the lath rigidly the full width of the lower flange of 
the joist. The elimination of the prong leaves a smooth 
surface to work against when applying the lath. In secur¬ 
ing the lath by means of the spring clip one end of the clip 
is passed through the mesh of the lath and hooked over the 


144 



















THE NATIONAL PRESSED STEEL COMPANY 


small vertical flange of the steel joist. With the clip in this 
position pass the other end of the clip through the mesh 
over the opposite vertical flange and hook tightly and rigid¬ 
ly in place. This can easily be done by tapping lightly with 
a hammer. Refer to page 45. 

After the spring clips are in place and the plaster 
applied, the clips are entirely imbedded in the plaster, 
which will prevent any movement whatever either of the 
lath or the clip. 

Furring Structural Steel. 

When steel joists are supported on structural steel 
beams these beams must be furred. The first operation 
necessary in furring is to secure furring clips to the bottom 
flanges of the structural steel members. The clips used 
for this purpose are so designed that they can be clamped 
around the bottom flange of the steel beam by a few raps 
of the hammer. Clips should not be spaced further than 
30" center to center along the flanges of the beam. After 
the furring clips are in place %" channels are laid parallel 
to the structural beam into seat of the furring clip which 
holds them in place, the %" channels acting as a support 
for the steel lath between furring clips. After the channels 
are placed the steel lath is applied by bringing it down from 
the bottom of the steel joists around the bottom of the 
rolled beam, properly lapping at all joists and wiring it 
with a soft No. 16 gauge wire to the channels. See 

P age 38 - , , • . 

Where deep structural steel supporting members are 
used in connection with steel floor joists, such as plate 
girders and deep girder beams, it is necessary to reinforce 
the steel lath. This is accomplished by placing light strap 
iron or metal bridging around the girders, spacing these 
straps not more than 30" center to center. To these straps 
wire V\" channels running lengthwise with the rolled beam, 
and in turn wire the lath to the channel. 

In cases where code requirements call for 2" of concrete 
all around structural members, the steel lath is to be 
wrapped clear up the sides of the rolled sections, split so as 
to go around steel joists, and all wired securely in place. 
Page 107. The proper thickness of cement plaster then to 
be applied to this lath. All plaster used on ceilings and 
walls in connection with Steel Lumber sections should be 
an accepted prepared plaster, prepared and mixed accord¬ 
ing to the manufacturer’s instructions, or other plaster, 
but should in any case have fire retarding qualities equal 
to cement plaster. For column and beam fire-protection, 
refer to page 109. 


145 




THE NATIONAL PRESSED STEEL COMPANY 


Plaster. 

The plaster used will of course depend upon the type 
and location of building. For many buildings the ordinary 
lime plaster will give sufficient protection. Where condi¬ 
tions call for maximum fire protection a cement mortar 
or good hardwall plaster should be used. All reference to 
plaster in this handbook is confined to cement plaster. 
This merely represents a basis of comparison and it is 
assumed that architects and engineers will accept any other 
plaster giving equally as good results. Refer to specifica¬ 
tions page 123. 

Framing. 

Where Steel Lumber joists are used in residential work 
it is practical to frame around stair openings with steel 
joists, particularly where used for first floor construction. 
When framing around stair openings for this type of build¬ 
ing it is advisable to place 4 " Steel Lumber I sections to act 



Steel Joist Columns Supporting Light Floor Load 






























THE NATIONAL PRESSED STEEL COMPANY 


as columns under the points where the steel joist headers 
frame into the steel joist trimmers. Of course, all loads 
must be considered and all Steel Lumber sections must be 
of the proper size and strength necessary to sustain all 
loads that may be transferred to them. When steel joist 
sections are used as columns in this manner always wrap 
them with lath and plaster to at least one inch thickness. 
In all cases where tail joists frame into headers, and header 
joists into trimmers, all connections must be bolted or 
riveted with not less than four bolts or rivets at each 
connection. Steel joists can be readily framed into each 
other by flattening out the small vertical flanges of the 
trimmers at the points where the header joist is to frame 
into them. Before headers can be fit into trimmers it will 
be necessary to rap the end of them with a hammer which 
will slightly decrease their depth, allowing them to snugly 
fit in between top and bottom flanges of trimmers. This in 
turn is true also where the tail joist frames into the header. 
See page 80. 



Steel Joist bearing partition supporting Steel Joist floor 


147 














































THE NATIONAL PRESSED STEEL COMPANY 


In some cases it is possible to eliminate the header 
member by using a Steel Lumber partition for supporting 
tail joist. When used in this manner the tail joists would 
rest on top of Steel Lumber supporting partition and be 
secured by rivet or bolt connections. This construction 
can be used in cases where the load may be too great for 
the depth of the joist that might be necessary to use as a 
header, as depth of this member must be governed by the 
size joists used in the main floor construction. See page 
80. All openings in the heavier type of buildings, such as 
stairs, elevators, openings for vent and heat ducts, when 
not built up with brick walls, also hatch-ways and smoke 
stacks, should be framed out with structural steel to sup¬ 
port Steel Lumber joists. A good method for framing 
around smoke stacks, heat and vent ducts, or any openings 
of this type, is to use structural steel channels as trimmers 
and headers. By riveting a 3 x 2p2 x structural steel 
angle to back of channel header, the Steel Lumber joists, 
which would be the tail joists, can be supported on same. 
In most any case the structural steel channel members 
can be made the same depth as the Steel Lumber joists, 
thus making a level ceiling below. See Page 81. 

When framing structural members around stairs or 
elevators, they must be of sufficient strength to carry Steel 
Lumber joist construction when supported on them, also 
stair and any other load that these structural members 
may be called upon to support. 

All small openings that might occur in floors, such as 
openings for foot warmers or a single vent or heat duct, 
can be framed out with Steel Lumber joist without addition¬ 
al supporting members. Page 80. 


Note—It is impossible to present in this book suffi¬ 
cient information to cover in detail every question which 
may arise. An effort has been made to present such data 
as will enable the experienced engineer and architect to 
design in steel with confidence as to the results to be 
secured. Structural Steel Fabricators stocking and 
fabricating National Steel Lumber sections are located 
in all principal cities. They will gladly furnish any further 
information that may be desired including estimates and 
quotations. 


148 









THE NATIONAL PRESSED STEEL COMPANY 


VARIOUS USES OF STEEL LUMBER 

National Steel Lumber sections are produced for use 
as joists and studs in floor and partition construction. 
'When used for this purpose they function to the best 
advantage and give absolute satisfaction. Familiarity 
with the material on the part of Architects, Engineers and 
Construction men has resulted in the sections being used 
for other purposes than those originally intended, in many 
instances such application gradually developing to the 
promise of standard practice. No doubt the future will 
develope many places where the rugged strength, uniform¬ 
ity, durability and shape of Steel Lumber sections can be 
applied with decided advantage. 

Canopies: 

Because of the light weight and relatively high strength, 
National Steel Lumber sections have proved very efficient 
when used in Canopy construction. The details of design 
are not materially changed by using these shapes. 

Bridge Floors: 

In bridge floor panels the joists are usedsimilarly as 
used in building floor construction, excepting that all 
sections are directly connected with supporting members. 
The result is a completed structure of unusual rigidity and 
light weight. 

Troughs or Chutes: 

Channel Sections make very good concrete chutes, the 
secondary flange preventing any slopping over the sides. 
Manufacturing plants conveying material such as wheat 
by gravity in chutes, find the channel sections efficient 
for the purpose. 

Roof Trusses: 

For many purposes, steel joist sections are commonly 
used in Roof Truss designs. They build up a strong, 
light weight truss for comparatively short spans. Care 
should always be taken in such construction that the 
trusses are amply braced laterally. 


149 




THE NATIONAL PRESSED STEEL COMPANY 


Lintels: 

For lintels over smaller openings use a design similar 
to sketch. The I joist carries the wall and applied 
floor loads, the necessary depth being determined by refer¬ 
ence to the loading tables, page 26. The hot rolled channel 
merely supporting and holding in position a few layers of 
face brick. The window frame can be nailed directly to 
the joist section, making the connection tight. 



Truck and Auto Frames: 

I Joists and Channel sections are used in the construc¬ 
tion of Truck and Auto frames. They may constitute the 
entire frame or be used only in cross braces. A straight, 
rolled section is much cheaper than an irregular shape 
formed on a press. Wherever such shapes can be used, 
the[ economy of National sections are in evidence. 


150 

















































































THE NATIONAL PRESSED STEEL COMPANY 




SECTION THRU SIDEWALLS 

Props and Shoring: 

In mines and all tunnel work steel joist sections may be 
used for Props and Roof Shoring. For Props cut the joists 
to desired length and by riveted angle detail connect 
bearing plates both ends. Slot these plates so that roof 
supports can be bolted to them. Joist sections for Roofs 
to have flanges slotted at both ends for bolting to prop 
bearing plates. 

Back planking and bracing supports as shown in sketch 
is very simple. This type of roof and wall support is 
quickly put into place, all steel sections to be given 
a second coat of good thick paint before installation. 


151 





















































Sidewalk and Pavement Forms: 

I he channel sections have proved practical for sidewalk 
and pavement forms. Their durability under rough hand¬ 
ling gives them long life. Use is shown in sketch, 
rhese forms cost practically the same as wood members 
for the same purpose and have all the advantages of steel. 



Concrete Forms: 

When building concrete retaining walls and similar 
work where economy necessitates the re-use of forms, 
the channel section proves efficient. The flanges are 
punched with 2" slots every eight inches to provide 
ample opportunity for bolted connections. Channels 
are supported at sufficient intervals with heavy timbers 
to maintain proper thickness of wall. 


152 


If 


























THE NATIONAL PRESSED STEEL COMPANY 



Tire Racks, Frames or Shelving 

Sketch shows Steel Lumber sections assembled to 
form tire storage racks. In this construction channels 
are employed for all members of the frame. The flange of 
the channel that serves as horizontal support or shelf is 
bent down slightly to conform with the curve of the tire, 
thus the sharp edge of the channel support is eliminated 
and a wider bearing provided for the tire. 

A similar assembly may serve as storage racks or shelv¬ 
ing. Practically any desired strength can be secured by 
the use of deeper channels or I sections. Either flange or 
web connections may be employed, the nature of National 
Steel L umber sections make these accessible to any kind 
of framing connections. 

If in assembly the various members are bolted together 
they can readily be disembled and reset as desired. 


ifc* 


153 





























THE NATIONAL PRESSED STEEL COMPANY 



Domes or Arch Roof Construction: 

Where roof construction is very complicated and the 
installation of standard floor construction not practical, 
the supporting members can be placed on closer centering 
and channel sections laid flat as shown over the top of 
supporting channels to give the desired contour. The 
bending of the channels can be done on the job at small 
cost and the roof built up as shown in sketch. Reinforcing 
rods can be placed as shown if conditions require, although 
the flanges of the channels provide ample reinforcing for 
all ordinary purposes. This type of roof construction is 
economical only where the contours required do not facili¬ 
tate the use of standard designs. In such case it is simple, 
effective and installed at considerable saving. 

In constructing this type of roof slab care should be 
taken that the channels are accessible for painting. Chan¬ 
nels placed in this manner are subjected to differences in 
temperature on the two faces resulting in a possibility of 
condensation. To prevent corrosion the exposed surface 
of the channels should be kept well painted. 

This opportunity for condensation does not exist 
where the steel joists are set vertically as in the standard 
floor or roof construction. There is no chance for corro¬ 
sion on the sections excepting when they are placed flat 
as in sketch. 


J VI 


154 








THE NATIONAL PRESSED STEEL COMPANY 



Piling: 1 ' 

On shallow operations where length of piles is not 
excessive, the channel sections provide an efficient inter¬ 
locking sheet piling. A wood guide is used in driving. 
This guide being only as long as the length of pile 
standing above ground surface. A wood buffer should 
be used on top of pile in driving. The channel sections 
show surprising durability on this kind of work and with 
proper use of driving guides give excellent results. 

When using National Steel Lumber for various pur¬ 
poses other than intended, always bear in mind that the 
sections cannot be expected to stand up under the same 
loading conditions as heavier shapes of the same size. 
Within the range of their limitations they are compara¬ 
tively more rugged than other steel shapes. Used under 
conditions beyond their range of adaptability, results 
secured will be unsatisfactory. Complying with the basic 
principles covered by the range of Steel Lumber adapta¬ 
bility, the service rendered by these sections will always 
merit approval. 

-- 


155 




























THE NATIONAL PRESSED STEEL COMPANY 


LIVE LOADS FOR FLOORS IN DIF 

Extracted From Building 
Weight of Floor Con 


No. 

City 

Dwell’g 
Apart¬ 
ments 
Tene¬ 
ments or 
Lodging 

Hotels 

Office 

Buildings 

First' 

Floor 

Upper 

Floors 

1 

Atlanta. 

60 

60 

150 

75 

2 

Baltimore. 

(b) 40 

40 

100 

50 

3 

Boston. 

50 

50 

125 

75 

4 

Buffalo. 

50 

50 

120 

50 

5 

Chicago. 

40 

50 

50 

50 

6 

Cleveland. 

70 

70 

125 

70 

7 

Dallas. 

40 

50 

150 

50 

8 

Detroit. 

40 

40 

125 

50 

9 

Kansas City. 

60 

60 

150 

75 

10 

Milwaukee. 

30 

30 

80 

40 

11 

Minneapolis. 

50 

50 

100 

75 

12 

New York. 

40 

40 

60 

60 

13 

New Orleans. 

(a) 40 

40 

125 

70 

14 

Omaha. 

50 

50 

50 

50 

15 

Philadelphia. 

40 

40 

120 

60 

16 

Pittsburgh. 

(b) 40 

50 



17 

Portland, Ore. 

(b) 50 

50 

125 

60 

18 

Providence. 

(c) 50 

50 

150 

75 

19 

San Francisco. 

40 

40 

125 

40 

20 

St. Louis. 

50 

50 

100 

60 

21 

St. Paul. 

40 

50 

50 

50 

22 

Seattle. 

40 

40 

125 

50 

23 

General Average of 






other Cities. 

40 

40 

100 

50 


Office and Public Rooms (a) 70, (b) 80, (c) 100. 
Corridors (d) 80. 

Fixed Seats (e) 80, (f) 75. 


156 



















































THE NATIONAL PRESSED STEEL COMPANY 




FERENT GLASSES OF BUILDINGS 

Codes of Various Cities, 
struction Not Included. 


Schools 

Build’gs 

for 

Public 

Assem¬ 

bly 

Stores 

Light 

Mfg. 

and 

Light 

Storage 

Garages 

(Public) 

Roofs 

(Flat) 

No, 

Class 

iooms 

Auditor¬ 

iums 

and 

Corri¬ 

dors 

75 

75 

90 

120 

120 

75 

'40 

1 

75 

100 

100 

100 

100 

90 

40 

2 

50 

100 

100 


125 

150 

40 

3 

50 

(d) 100 

(e) 100 

120 

120 

120 

30 

4 

75 

100 

100 

100 

100 

100 

40 

5 

70 

70 

100 

(g)100 

125 

(i) 100 

35 

6 

60 

90 

(f) 100 

120 

120 

80 

25 

7 

50 

80 

(f) 100 

(g)100 

125 

100 

30 

8 

60 

90 

90 

120 

120 

80 

50 

9 

40 

60 

(k) 50 

100 

100 

80 

30 

10 

75 

(n) 100 

125 

100 

100 

100 

50 

11 

75 

75 

100 

120 

120 

120 

40 

12 

60 

125 

(1) 125 

125 

125 


30 

13 

50 

75 

100 

100 

100 

100 

30 

14 

75 

100 

100 

(j) 100 

120 

120 

30 

15 






125 

40 

16 

60 

75 

80 

(g)100 

125 

(g) 80 

40 

17 

60 

125 

(m) 125 

125 

125 

150 

40 

18 

75 

125 

(0125 

100 

125 

100 

30 

19 

75 

100 

100 

150 

100 

100 

30 

20 

60 

125 

100 

125 

100 

100 

30 

21 

50 

100 

100 

100 

125 


40 

22 

60 

80 

(e) 90 

100 

125 

80 

40 

23 


First Floor (g) 125, (h) 100, (i) 150, (j) 120. 
Drill or Dance Halls (k) 100, (1) 150, (m) 200. 
Assembly Rooms (n) 125. 


157 



































THE NATIONAL PEESSED STEEL COMPANY 


Bending Moments and Deflection of Beams 
for Usual Methods of Loading 


P & W = Total Load I = Moment of Inertia 

L = Length of Net Span E = Modulus of Elasticity 

M = Maximum Bending Moment S = Maximum Shear 


Beam Fixed at One End and Loaded at Other 



Safe load = 34 that shown in tables 
M = PL at point of support 
S = P at point of support 

Deflection = 


Beam Fixed at One End and Uniformly Loaded 


'//A 

w 

V/Zl 


Ip 

v _. 




Safe load = 34 that shown in tables 
M = — : point of support 
S =W point of support 
Deflection = - 7 ^ 7 - 


Beam Supported at Both Ends, Single Load in Middle 

Safe load = 34 that shown in tables 



M =~~ middle of beam 

4 

p 

S = — at points of support 

Deflection = - .^ I l T 
48 El 


Beam Supported at Both Ends and Uniformly Loaded 

Safe load = that shown in tables 


- 




-'-i 


M = 


WL 

8 


at middle of beam 





Deflection = 


at points of support 
5WL 3 


384EI 


158 



















































THE NATIONAL PRESSED STEEL COMPANY 


Beam Continuous Over Support at One End 
Uniformly Loaded 




Safe load = l}/s that shown in tables 
M at middle of beam 

S =~y~ at points of support 


Deflection 


3WL 3 
384 El 


Beam Continuous Over Support at Both Ends and 

Uniformly Loaded 



Safe load = V/i that shown S=-y-at point of support 



at middle of beam 


Deflection = 


WL 3 
384 El 


Beam Supported at Both Ends—Single Unsymmet- 

rical Load 

L 2 


■A 


Safe load = that given in tables X 
M under load 


8 AB 


s = 


A End = 


PB 


B End = 


L 

PA 


w Deflection = A) \/MA(2L-A) 


Beam Supported at Ends—Two Symmetrical Loads 

Safe load = that shown in tables X-^- 
PA 



M = — between loads 

p 

S = — bet. load & nearest support 


Deflection- 


PA 


48 El 


(3L 2 —4A 2 ) 


159 




















































THE NATIONAL PRESSED STEEL COMPANY 

WEIGHTS OF BUILDING MATERIALS 


Wt. in 

Material and Purpose for Which Used 

Lbs. per 

• 

Sq. Ft. 

FLOORS 

* % 

i/i" Oak finish flooring. 

3K 

Yi Oak finish flooring. 

IK 

Maple finish flooring. 

3 

Y% n Maple finish flooring. 

l K 

Yellow Pine sheathing—1" thick. 

4 

Stone Concrete fill per inch of thickness. 

12 

Cinder Concrete fill per inch of thickness. 

9 

Asphalt Mastic flooring IK" thick. 

18 

Cement or Terrazo finish per inch of thickness. 

13 

Solid Flat Tile on 1" mortar bed. 

23 

CEILINGS 


Plaster on Tile or Concrete. 

6 

Plaster on Metal Lath.. 

7 

Metal Lath. 

y. 

Suspended Metal Lath and Plaster. 

9 

ROOFS 


Yellow Pine sheathing 1" thick. 

4 

Slate K" thick. 

Q 

Cement Tile. 

16 

Cinder Fill per inch thickness. 

3K 

Three Ply Ready Roofing. 

1 

Four Ply Felt and Gravel. 

5K 

Five Ply Felt and Gravel. 

6 

WALLS 


9" Brick Wall—unplastered. 

84 

13" Brick Wall—unplastered. 

121 

18" Brick Wall—unplastered. . . . 

168 

22" Brick Wall—unplastered. 

205 

26" Brick Wall—unplastered. 

243 

4" Brick 4" Tile Backing—unplastered.. . 

60 

4" Brick 8" Tile Backing—unplastered.... 

75 

y" Brick 4" File Backing—unplastered. . 

102 

8" Tile—unplastered. 

33 

12" Tile—unplastered. 

45 

Plaster on Brick or Tile Walls—one side . 

5 



160 













































THE NATIONAL PRESSED STEEL COMPANY 


WEIGHTS OF BUILDING MATERIALS 


Kind and Purpose for Which Used 


Wt. in 
Lbs. per 
Sq. Ft. 


PARTITIONS 

3 " Clay Tile—both sides plastered. 

4" Clay Tile—both sides plastered. 

6" Clay Tile—both sides plastered. 

8" Clay Tile—both sides plastered. 

3" Gypsum Block—both sides plastered 
4" Gypsum Block—both sides plastered 
5" Gypsum Block—both sides plastered 
6 " Gypsum Block—both sides plastered 

2 " Solid Plaster. 

4" Hollow Plaster. 


27 

28 
35 
41 
20 
22 
24 
26 
20 
22 


MASONRY 


Kind 


Concrete, cinder. 

Concrete, stone. 

Concrete, reinforced stone 

Brick, masonry, soft. 

Brick, masonry, common. 
Brick, masonry, pressed. . 

Granite, dressed. 

Marble. 

Limestone. 

Sandstone. 


Wt. in 
Lbs. per 
Cu. Ft. 


110 

144 

150 

100 

125 

140 

165 

165 

162 

150 


MISCELLANEOUS 



Weight 

lbs. 

Cement, Portland, per barrel. 

376 

Cement, Portland, per cubic foot. 

85 to 90 

Lime, per barrel... 

225 

Sand, per cubic foot. 

90tol06 

Gravel, per cubic foor. 

120 

Cinders, per cubic foot. 

40 

Dimension Lumber, per foor B. M. 

3 

Iron, per cubic foot. 

480 

Steel, per cubic foot. 

489.6 

Water, ar 32° F., per cubic foot. 

62.417 


























































THE NATIONAL PRESSED STEEL COMPANY 


C/5 

C/5 

05 

v~ 

■M 

in 

0) 

i* 

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03 

s 

u 

z 


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Co- 

efficient 

43.0510 

44.7559 

46.4938 

48.2648 

50.0690 

51.9062 

53.7766 

55.6800 

57.6166 

59.5862 

Clear 
Span in 
Feet 

~HCSfOT*<iO'Ot'^00O'© 

lO^OiOiOiOUOiOLOiO'O 

Co¬ 

efficient 

27.8234 

29.1972 

30.6041 

32.0441 

33.5172 

35.0234 

36.5628 

38.1352 

39.7407 

41.3793 

Clear 
Span in 
Feet 

— CNr'3-tvO'Of'.OOO'O 

•^<T*T}lTj'T*TjlTi<Tj<T*ir) 

Co¬ 

efficient 

15.9062 

16.9490 

18.0248 

19.1338 

20.2759 

21.4510 

22.6593 

23.9007 

25.1752 

26.4828 

Clear 
Span in 
Feet 

-HCNro^iO'Or^ooo© 

Co¬ 

efficient 

7.2993 

8.0110 

8.7559 

9.5338 

10.3448 

11.1890 

12.0662 

12.9766 

13.9200 

14.8966 

Clear 
Span in 
Feet 

0 

*-«c^r^Tt«iO'Or^00ON© 

CNCNCNCNCNCNCNCNCSrO 

Co¬ 

efficient 

2.0028 

2.3834 

2.7972 

3.2441 

3.7241 

4.2372 

4.7834 

5.3628 

5.9752 

6.6207 

Clear 
Span in 
Feet 

rHCNP^^tlO'ONOOa© 

HHHHHHHHHCS 

Co¬ 

efficient 

'OCSOCOOOO'OpONN 

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Span In 
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162 




































163 





































































































THE NATIONAL PKESSED STEEL COMPANY 


STRUCTURAL TIMBER 

Commercial timbers which are in common use in 
building construction are not uniform in character. 
Therefore in the design and construction of wood 
frame structures great care should be exercised. The 
strength of structural timbers depends upon—the kind '6f 
wood, the age of the tree, the time of year in which it is 
felled, the method of sawing, the character of the season¬ 
ing with the resulting moisture content, the proportion of 
heart wood to sap-wood and the proportion of knots to 
clear wood. 

As a result of the various factors effecting the strength 
of timber, the working unit stresses approved by the build¬ 
ing laws of different cities vary widely. However, research¬ 
es by technical and engineering associations and by the 
Forestry Division have established unit stresses for various 
kinds of wood which actual construction has approved as 
good practice. 

The safe load tables for wood joists which follow may 
be accepted as reliable. The uniformly distributed safe 
loads are given for rectangular sections one inch thick. 
The safe load for a beam of any thickness is found by 
multiplying the tabular value by thickness of the beam 
in inches. The safe loads include the weight of the beam 
and are based on the assumption that the beams are 
braced against lateral deflection. 

The deflection of beams intended to carry plastered 
ceiling shouldnot exceed l/360ofthe span. Themaximum 
spans for this limit are given. 

In the use of wood floor joists care should be taken 
that unavoidable knots are at the top or compression side 
of beams instead of in the lower or tension side. The 
details of construction should be such as to eliminate in 
so far as pdssible the evil effects caused by the shrinkage 
of the joists. 


I 


164 






THE NATIONAL PRESSED STEEL COMPANY 


STRUCTURAL TIMBERS 


Average Safe Allowable Working Unit Stress, in Pounds 

per Square inch. 


Kind of Timber 

Weight 
per Foot 

Bending 

Shearing 

Compression 

Safe 

Stress 

Modulus 

of 

Elasticity 

With 

Grain 

Across 

Grain 

End § 

Bearing h 

W 

Grain 

m 

Ui 

<D .2 

'i ss 

• c Q 
J3 

oh2 

Across 

Grain 

Safety Factor. 


6 

2 

4 

4 

5 

5 

4 

White Oak. . . . 

4.16 

1200 

750000 

200 

1000 

1400 

1000 

500 

White Pine. ... 

1.98 

800 

500000 

100 

500 

1100 

750 

200 

Long Leaf Pine. 

3.17 

1200 

750000 

150 

1250 

1400 

1000 

350 

Douglas Fir. . . 

2.65 

1000 

750000 

150 

.... 

1200 

900 

200 

Short Leaf Pine 

2.65 

1000 

650000 

125 

1000 

1200 

900 

250 

Spruce. 

2.08 

900 

600000 

100 

750 

1100 

800 

200 

Hemlock. 

2.08 

800 

500000 

125 

600 

1200 

800 

150 

Cypress. 

2.39 

900 

500000 

125 

• • • • 

1000 

800 

200 

Cedar. 

1.93 

750 

400000 

100 

400 

1000 

700 

200 

Redwood. 

2.01 

800 

350000 

100 


900 

700 

150 

Tamrack. 

3.00 

900 

600000 

150 

.... 

1000 

750 



Maximum Spans in Feet for Permanent Loads 


Depth of Wood Beams in Inches 


Wood 

2 

4 

6 

8 

10 

12 

14 

16 

18 

20 

22 

24 

White Oak 

2.3 

4.7 

7.0 

9.3 

11.6 

13.9 

16.3 

18.6 

20.9 

23.2 

25.6 

27.9 

Long Leaf 
Pine.... 

2.8 

5.5 

8.3 

11.0 

13.8 

16.5 

19.3 

22.0 

24.8 

27.6 

30.3 

33.1 

Short Leaf 
Pine. 

3 0 

6 0 

9.0 

12.0 

15.0 

17.9 

20.9 

23.9 

26.9 

29.9 

32.9 

35.9 

Hemlock. . 

3.0 

6.0 

9.0 

12.0 

15.0 

17.9 

20.9 

23.9 

26.9 

29.9 

32.9 

35.9 

Douglas Fir 

2.8 

5.6 

8.4 

11.2 

14.0 

16.7 

19.5 

22.3 

25.1 

27.9 

30.7 

34.5 

Spruce.... 

2.9 

5.8 

8.7 

11.6 

14.6 

17.5 

20.4 

23.3 

26.2 

29.1 

32.0 

37.9 


Shows the maximum span in lineal feet for a maximum 
deflection of 1/360 of the span. 


165 






















































































Safe Loads in Pounds Uniformly Distributed. For Rectangular Beams One Inch Thick 

Allowable Fibre Stress 1200 Pounds per Square Inch 

To find the safe load for any size wood beam, take the load shown in tables for the given beam depth and multiply 
by the width of beam in inches. 


THE NATIONAL PRESSED STEEL COMPANY 


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166 


To determine the maximum deflection at center of wood beam under uniform loading divide the given coefficient for 
deflection by the depth of beam in inches. If deflection amounts to more than 1/360 of the span then a deeper beam should 
be used. 


















































REQUIRED WIDTH OF WOOD JOIST 

Equaling the Strength of National Steel Joists. 


THE NATIONAL PRESSED STEEL COMPANY 






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167 


























































































THE NATIONAL PRESSED.STEEL COMPANY 


BOARD MEASURE 

This table shows the exact number of feet in any piece 
of dimension timber. 


Length in Feet 


in 

Inches 

10 

12 

14 

16 

18 

20 

22 

24 

26 

28 

30 

*32 

2 x 4... 

6! 

8 

9} 

10! 

12 

13} 

14! 

16 

17} 

18} 

20 

21} 

2 x 6. .. 

10 

12 

14 

16 

18 

20 

22 

24 

26 

28 

30 

32 

2 x 8... 

13} 

16 

18! 

21} 

24 

26! 

29} 

32 

34} 

37} 

40 

42} 

2 xlO... 

16 § 

20 

23} 

26! 

30 

33} 

36} 

40 

43} 

46! 

50 

53} 

2 xl2... 

20 

24 

28 

32 

36 

40 

44 

48 

52 

56 

60 

64 

2 xl4... 

23} 

28 

32} 

37} 

42 

46} 

51} 

56 

60! 

65} 

70 

74} 

2 xl6... 

26f 

32 

37} 

42} 

48 

53} 

58! 

64 

69} 

74! 

80 

85} 

2}xl2... 

25 

30 

35 

40 

45 

50 

55 

60 

65 

70 

75 

80 

2}xl4... 

29} 

35 

40 § 

46! 

52} 

58} 

64} 

70 

75 Jj 

81} 

87} 

94} 

2}xl6... 

33} 

40 

46! 

53} 

60 

66! 

73} 

80 

86} 

93} 

100 

106} 

3 x 6... 

15 

18 

21 

24 

27 

30 

33 

36 

39 

42 

45 

48 

3 x 8 . .. 

20 

24 

28 

32 

36 

40 

44 

48 

52 

56 

60 

64 

3 xlO... 

25 

30 

35 

40 

45 

50 

55 

60 

65 

70 

75 

80 

3 xl2... 

30 

36 

42 

48 

54 

60 

66 

72 

78 

84 

90 

96 

3 xl4... 

35 

42 

49 

56 

63 

70 

77 

84 

91 

98 

105 

112 

3 xl6... 

40 

48 

56 

64 

72 

80 

88 

96 

104 

112 

120 

128 

4x4... 

13} 

16 

18! 

21} 

24 

26! 

29} 

32 

34! 

37} 

40 

42} 

4 x 6 .. . 

20 

24 

28 

32 

36 

40 

44 

48 

52 

56 

60 

64 

4 x 8 ... 

26f 

32 

37} 

42! 

48 

53} 

58! 

64 

69} 

74! 

80 

85} 

4 xlO... 

33} 

40 

46} 

53} 

60 

66} 

73} 

80 

86} 

93} 

100 

106} 

4 xl2... 

40 

48 

56 

64 

72 

80 

88 

96 

104 

112 

120 

128 

4 xl4... 

46! 

56 

65} 

74! 

84 

93} 

102! 

112 

121} 

130! 

140 

149} 

6 x 6. .. 

30 

36 

42 

48 

54 

60 

66 

72 

78 

84 

90 

96 

6 x 8 .. . 

40 

48 

56 

64 

72 

80 

88 

96 

104 

112 

120 

128 

6 xlO... 

50 

60 

70 

80 

90 

100 

110 

120 

130 

140 

150 

160 

6 xl2... 

60 

72 

84 

96 

108 

120 

132 

144 

156 

168 

180 

196 

6 xl4... 

70 

84 

98 

112 

126 

140 

154 

168 

182 

196 

210 

224 

8 x 8.. . 

53} 

64 

74! 

85} 

96 

106! 

117} 

128 

138! 

149} 

160 

170} 

8 xlO.. . 

66! 

80 

93} 

106! 

120 

133} 

146! 

160 

173} 

186! 

200 

213} 

8 xl2... 

80 

96 

112 

128 

144 

160 

176 

192 

208' 

224 

240 

256 

8 xl4... 

93} 

112 

130! 

149} 

168 

186! 

205} 

224 

242} 

261} 

280 

298} 

10 xlO... 

83} 

100 

116! 

133} 

150 

166! 

183} 

200 

216! 

233} 

250 

266} 

10 xl2... 

100 

120 

140 

160 

180 

200 

220 r 

240 

260’ 

280 

300 

320 

10 xl4... 

116! 

140 

163} 

186! 

210 

233} 

256! 

280 

303} 

326! 

350 

373} 

10 xl6... 

133} 

160 

186! 

213} 

240 

266! 

293} 

320 

346! 

373} 

400 

426} 

12 xl2... 

120 

144 

168 

192 

216 

240 

264 

288 

312 

336 

360 

384 

12 xl4... 

140 

168 

196 

224 

252 

280 

308 

336 

364 

392 

420 

448 

12 xl6... 

160 

192 

224 

256 

288 

320 

352 

384 

416 

448 

480 

512 

14 xl4... 

163} 

196 

228! 

261} 

294 

326! 

359} 

392 

424! 

457} 

490 

522} 

14 xl6... 

186! 

224 

261} 

298} 

336 

373} 

410} 

448 

485} 

522! 

560 

597} 


t 


168 













































THE NATIONAL PRESSED STEEL COMPANY 


NATIONAL STRIP STEEL 

Straight standard carbon and special or standard 
alloy analyses especially for Pressing, Stamping and Deep 
Drawing in following sizes: 

Widths—Minimum, 3"; maximum, 14" to 24" (under 
8" sheared edges). 

Gauges—No. 15 (.072") to No. 00 (.380"). 

Lengths—Hot Coiled 80'to 120';or cut to specified lengths. 
Finish and Treatment—Plain Black, Pickled, Oiled, 
Limed or Annealed as desired. 


STANDARD EXTRAS IN CENTS PER 100 LBS. 


Width 

9 Ga. 
.148" 
and 

Heavier 

Under 
9 Ga. 
to and 
Inch 
12 Ga. 
.109" 

13 Ga. 
.095" 

14 Ga. 
.083" 

15 Ga. 
.072" 

16 Ga. 
.065" 

3 ". 

base 

$0.05 

$ 0 . 10 

$ 0 . 10 

$ 0 . 10 

$0.15 

3*" to 4 ". 

base 

.05 

. 10 

. 15 

.20 

.30 

4*" to 5 ". 

base 

. 10 

.15 

.20 

.30 

.50 

5^" to 6 ". 

base 

. 10 

.20 

.30 

.40 

.70 

6*" to 8 ". 

. 10 

.20 

.30 

.45 

.60 

.80 

8*" to 10 ". 

. 10 

.20 

.40 

.55 

.80 

1.05 

10 *" to 12 M ". 

.20 

.30 

.50 

.75 

.95 

1.25 

12*" to 15 ". 

30 

.40 

.60 

.90 



15*" and wider 

40 

60 

75 

1.00 



Extra for slitting. . . 

.25 

.25 

.25 

.25 

.40 

.40 

Extra for pickling. . 

.40 

.40 

.45 

.50 

.55 

.60 


05 

10 

20 


In coils or cut to length 5 feet and over including shorter 
pieces that accrue in cutting. 

Cutting to length 5 feet and over without 

short pieces.10% extra 

Annealing.$0.50 

Cutting to length over 48, under 60 inches. 

Cutting to length over 24 to 48 inches inclusive. . . . 
Cutting to length over 12 to 24 inches inclusive. . . . 
Cutting to length under 12 inches—on application 

at least.(minimum) .30 

For intermediate thickness the extra for next lighter 
will apply. Birmingham wire or Stubb’s gauge (see 

opposite page) applies on this list. 

Less than 2000 to 1000 pounds.$0.15 

Less than 1000 pounds. -35 

Charges for other than mill inspection will apply 
according to work involved. 


169 






































THE NATIONAL PRESSED STEEL COMPANY 


GAUGE EQUIVALENTS 

And Weights per Lineal Foot 


Gauge 

No. 

Birmingham or Stubbs 

U. S. Standard 

Decimal 

Thickness 

Fractions of 
an Inch 

Decimal 

Thickness 

Lbs.perlin.ft. 
1' wide 

0000 

.454 

1.54 

.4063 

A — .016 

000 

.425 

1 44 

.3750 

A— .031 

00 

.380 

1 29 

.3438 

A— .047' 

0 

.340 

1.16 

.3125 

A— .063 

1 

.300 

1.02 

.2813 

A— -078 

2 

.284 

.966 

.2656 

A— .094 

3 

.259 

.881 

.2500 

A— .109 

4 

.238 

.809 

.2344 

y%— .125 

5 

.220 

.748 

.2188 

A— .140 

6 

.203 

.690 

.2031 

A— .156 

7 

.180 

.612 

.1875 

ft— .172 

8 

.165 

.561 

.1719 

A— .188 

9 

.148 

.503 

.1563 

H— .203 

10 

.134 

.456 

.1406 

A— .219 

11 

.120 

.408 

.1250 

H— .234 

12 

.109 

.371 

.1094 

Yx — .250 

13 

.095 

.323 

.0938 

A— -281 

14 

.083 

.282 

.0781 

A— .313 

15 

.072 

.245 

.0703 

-344 

16 

.065 

.221 

.0625 

H— .375 

17 

.058 

.197 

.0563 

H— .406 

18 

.049 

.167 

.0500 

A— .438 

19 

.042 

.143 

.4038 

.469 

20 

.035 

.119 

.0375 

Vi — .500 

21 

.032 

.109 

.0344 

H— -531 

22 

.028 

.095 

.0313 

A— .563 

23 

.025 

.085 

.0281 

M— -594 

24 

.022 

.075 

.0250 

Wr- .625 

25 

.020 

.068 

.0219 

If— .656 

26 

.018 

.061 

.0188 

U— .688 

27 

.016 

.054 

.0172 

II— .719 
Vx— .750 

28 

.014 

.047 

.0156 

29 

.013 

.044 

.0141 

If— .781 
H— .813 

30 

.012 

.040 

.0125 

31 

.010 

.034 

.0109 

H— .844 

32 

.009 

.030 

.0102 

Vt— .875 

33 

.008 

.027 

.0094 

M— .906 
H— .938 

34 

.007 

.024 

.0086 

35 

.005 

.017 

.0078 

H— .969 

36 

.004 

.014 

.0070 

1 — 1.000 


The Birmingham (or Stubbs) Gauge is universally recognized as 
Standard by manufacturers of Hot Rolled Strip Steel. Specifications 
by gauge number will be interpreted accordingly unless otherwise 
stated. 


170 





















THE NATIONAL PRESSED STEEL COMPANY 


INDEX 

PAGE 

Accessories.12, 21 

table of quantities. 62 

Adaptability, steel construction.139 

Advantages of steel construction.135 

Analysis, chemical, of steel joists...120, 134 

Anchors, joist...86, 92 

Angles, shelf.88-91 

location of—...90, 91 

Area of finished columns.70, 119 

Application of steel lath. 42 

Asphalt mastic flooring, weight of.160 

Atlanta, code specifications for live loads.156, 157 

Auto frames.150 

Balcony construction. 96 

Baltimore, code specifications for live loads.156, 157 

Barrel cement, weight of. 161 

Base, pricing of steel joist. 12 

Beams, coefficients for deflection.162 

general formulae for flexure.158, 159 

stresses, safe for deflection.163 

Birmingham gauge.170 

Beam Clips, description. 36 

application of._.36, 85 

table for designing—... 37 

Beam Furring Clips, description of. 38 

application of._.38, 107 

table for designing. 39 

Beam costs.68, 69 

Beam fireproofing.106, 107 

Bearing partitions—...78, 82, 147 

Bearing, for steel joists.22, 84-91 

specifications for.122 

Billets.132 

Board measure, table of. 168 

Boston, code specifications for live loads.156, 157 

Bracing of steel joists.23, 49-53 

Brick, masonry, weights of.160, 161 

Bridge floor construction.149 

Bridging, description of.21, 49-53 

function of. 49 

installation of.... ; .-. 52 

table of quantities...62 

table of sizes, strap bridging. 51 

specifications of. 112 


171 
















































I 


THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

Buffalo, code specifications for live loads.156, 157 

Building materials, weights of..160, 161 

Building code, live load specifications.156, 157 

Canopies.149 

Ceilings, weights of.160 

specifications for suspended.124 

suspended. 97 

Ceiling hangers.. 97 

Cement, barrel, weight of... 161 

flooring, weight of.160 

Channels, cuts of sections, Steel Lumber.20, 133 

safe loading tables structural steel...,.127 

Chemical analysis, steel joists....120, 134 

Chicago, code specifications for live loads..156, 157 

Cinders, weights of.161 

Cleveland, code specifications for live loads...-.156, 157 

Clips, table of quantities. 62 

beam. 36 

beam furring.. 38 

roof bracing steel joists..100 

spring lath.. 44 

Code specifications, various cities.156, 157 

Coefficients for deflection. .162 

Coils...133 

Columns, comparison in design and weight.118 

costs..70, 71 

fireproofing of.__.108, 109 

Concentrated floor loads...128 

Concrete, design of slab.129, 143 

footings.111-115 

forms.152 

stairways.,.102 

strength of slab.129 

weight of. 161 

Conduits, installation of.79, 93-95 

Construction details.74, 101 

Continuous bridging.21, 49 

Common formulae.158, 159 

Comparison, floor design..’...131 

costs. 64-73 

steel and wood joists.. 140, 167 

steel joists with rolled I beam. v _„ 9 

weights of construction.116-119 

Coping—. 87 


172 















































THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

Corrosion, steel joists.137 

Cost data. 64 

Crippling of webs, steel joists. 34 

Curb forms.152 

Cuts of sections, standard steel joists.13-20 

accessory materials... 21 

Cutting extras, strip steel..169 

Cutting tolerances, steel joists. 12 

Cutting of steel joists. 134 

Dallas, code specifications for live loads.156, 157 

Dance hall or assembly floor design.128 

Dead load, comparison of firesafe floor designs.131 

calculation for steel lumber construction.130, 139 

steel construction.116-119 

Decimal gauges.170 

Deflection, coefficients for.162 

limit of span, structural timber.165 

unit fibre stresses...163 

of steel joists.. 11 

Depreciation of steel construction.136 

Description of steel joists.9, 12, 120 

Designing data. 22 

formulae...158, 159 

Designation of steel joists. 12 

Detroit, code specifications for live loads.156, 157 

Dimensions of, steel joists.13-20 

beam clips..=..21, 37 

beam furring clips.21, 39 

spring lath clips.....21, 48 

shelf angle location.90, 91 

Dome roof construction.-.154 

Durability of steel construction.136 

Economy of steel construction.63, 116-119, 137 

Economical spans, steel joists.22, 67 

Erection of steel joists.54, 140, 142 

Estimating data... 56 

steel joists. 56 

accessory quantities.. 62 

Explanatory notes, safe loading tables... 23 

Fibre stresses, safe for various spans.163 

for designing...22-24 

structural timbers.165 

Field for use of steel lumber.12, 139 

Fill, concrete..-.132 


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THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

Fireproof qualities of steel joists.7, 9, 135 

Fireproofing, structural steel.106-109 

requirements for.7, 9 

Firesafe first floors..—.141 

Flexure of beams, formula for.158, 159 

Floor construction, standard steel joist....55, 75, 101 

bridging for.—....49-53 

comparison of weight...117, 131 

comparison of costs.65-67 

concrete fill.121, 129, 143 

dead load, method of calculating.131 

description.120 

development of—.116 

floor finishes.76-79 

floor loads—.156, 157 

framing details (see construction details).125 

steel lath for. 40 

spacing of joists—.23, 128, 142 

specifications....120 

Footings, design—.111-115 

comparative costs.72, 73 

table of quantities.113-115 

unit stresses for.Ill 

Formulae, bending moments.158, 159 

web buckling. 34 

Framing details, floors—.80, 81, 146, 147 

structural steel framing.125-127 

dimensions for locating shelf angles.90, 91 

Function of bridging. 49 

steel joists. 5 

Furring, beams—.107 

clips.21, 39 

Garage floors.128 

Gauge equivalents.170 

United States standard.170 

Birmingham.170 

General information.132-148 

Grand stand construction. 96 

Granite, masonry, weight of.161 

Gypsum block, weight of.161 

Heating pipes, installation.93, 142 

Hangers, pipe-. 93, 95 

Identification of steel lumber sections. 12 

Installation, conduits, pipes, etc.93, 95, 142 

I_ 


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THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

steel joists...54, 140, 142 

strap bridging...... 52 

time of steel construction....138 

Iron, weight of—.161 

Joists, steel, analysis of.9, 120, 134 

accessories..12, 21 

analysis of sections.9, 120, 134 

base for pricing. 12 

bearings for...78, 84, 89, 122 

chemical analysis.120 

coefficients for deflection.162 

comparison of weight.116-119, 131 

with wood joists...167 

corrosion.137 

cutting of.134 

cutting tolerances. 12 

deflection.. 11 

designation of._. 12 

designing data. 22 

description of. 12 

development of.. 8 

economy of..63, 137 

economical span..22, 67 

erection.142 

estimating data. 56 

fibre stress.. 24 

field for use—. 12 

fireproofing of..,,. 7 

fireproof qualities..135 

floor construction, standard.55, 75, 101, 120 

formulae for calculation.158, 159 

framing of...80, 81, 133, 146, 147 

forming of—.133 

function of. 5 

installation of—. 54 

lateral bracing.23, 54 

maximum strength, temperature..—. 7 

method of production...9, 132 

methods of supporting—.22, 84-91, 141 

painting.. 134 

panel construction..55, 101 

physical qualities—.9, 134 

points of merit. 10 

properties of.23-25 


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THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

safe loading tables._.23-33 

spacing.23, 122, 142 

special sections... 12 

specifications..120 

steel, comparison with wood joists.167 

stresses, safe for deflection.163 

wall anchors for...86, 92 

welding of.133 

weight of.13, 20, 130 

ultimate strength. 23 

web resistance. 34 

Kansas City, code specifications for live loads_156, 157 

Lath, steel..40-43 

adapted to steel joists... 40 

basis of merit. 40 

erection of.42, 44, 48, 143 

specifications for.121 

Lath clips, description.44-48, 144 

number clips required. 48 

method of installing. 45 

manner packed.-. 48 

method of separating clips in package... 48 

spacing on floors and ceilings..46-47 

Lateral bracing, steel joists.23, 54 

Length of sections, steel joists....133 

Lintels.150 

Limestone masonry, weight of..161 

Live load specifications...156-157 

Loading tables.23-33 

Locating shelf angles. 90, 91 

Location of welds, steel joists.133 

Lumber, weight of.161 

Mastic flooring, weight of.160 

Marble, weight of.161 

Masonry walls, weight of.161 

Maple flooring, weight of. 160 

Maximum spans for structural timbers.165 

Metal lath, (see also lath) sheet sizes... 23 

Method, estimating steel joists. 56 

framing openings...80, 81 

fireproofing structural steel.106-109 

installing lath clips. 45 

producing steel lumber. 132 

Milwaukee, code specifications for live loads.156, 157 


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THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

Minneapolis, code specifications for live loads.156, 157 

Moments of inertia, steel joists. 25 

bending for beams.158, 159 

Nails, attaching bridging to steel joists, quantity. 62 

Nailing strip.76, 79, 94, 143 

specifications for.121 

National strip production.132 

National strip steel.169 

New Orleans, code specifications for live loads.156, 157 

Oak flooring, weight of.160 

Omaha, code specifications for live loads.156, 157 

Outlet boxes, method of attaching. 94 

Painting, steel joists.134 

Partition construction, illustrations of...78, 79, 82 

safe loading tables—. 32 

Pavement forms...152 

Philadelphia, code specifications for live loads_156, 157 

Piling, sheet.155 

Piping, installation with steel joists—.79, 93-95 

Pittsburgh, code specifications for live loads.156, 157 

Placing concrete on floor lath.,.144 

Plaster, specifications for.123 

weight of...•*..161 

Points of merit, steel joist floors. 10 

Portland, code specifications for live loads.156, 157 

Pounds of steel joist per sq. ft. floor area.:.57-61 

Production of strip steel.132 

Properties of sections, steel joists....... 25 

Providence, code specifications for live loads.156, 157 

Rivet sizes, steel joist connections.80, 83 

Rolled steel sections, framing members—.126, 127 

Rigidity of steel construction.139 

Roof construction.97-100 

spacing of joists—....122, 142 

Roof trusses, steel joists.149 

Roofing materials, weight of.161 

Safe loading tables, steel joists.23-33 

rolled steel framing members.126, 127 

structural timbers.166 

explanatory notes. 23 

Sandstone, weight of.161 

San Francisco, code specifications for live loads ....156, 157 

Screeds, nailing—.-.76, 79, 94, 143 

Seattle, code specifications for live loads..156, 157 


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THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

Sheet metal gauges.170 

Shelf angles, location of.90, 91 

Shelving....153 

Sheet Piling. 155 

Sidewalk forms..-.152 

Simplicity of steel construction—. 140 

Single strap bridging, sizes of. 51 

Sizes of, beam furring clips.21, 39 

Beam clips.21, 37 

Spring lath clips.21, 48 

Soundproof qualities, steel joist floors.136 

Spacing of steel joists..23, 142 

Specifications.120-124 

live loads..156, 157 

bridging—.121 

plaster.123 

steel joists.120 

steel lath. 121 

suspended ceiling—.124 

Special steel joist sections. 12 

Spring lath clips.21, 44-48, 144 

number required. 48 

manner packed . 48 

weight of—. 48 

spacing.. 46 

Stairway construction..102, 105 

Standard steel joist floor construction...55, 75, 101 

Standard extras for strip steel.169 

Standard sections..13-20 

Steel, weight of.161, 170 

Steel Construction, adaptability of.139 

cost data. 64 

dead weight of.139 

economy of.63, 137, 116, 119 

erection of.54, 140, 142 

rigidity.—.139 

simplicity of.140 

Steel joist (see also joist).13-20 

Steel lath.21, 40-43 

application of....42, 48, 143 

basis of merit.~. 40 

specifications..121 

St. Louis, code specifications for live loads—.156, 157 

Strap bridging (see also bridging)—. 21 


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1 


THE NATIONAL PRESSED STEEL COMPANY 


INDEX—Continued 

PAGE 

Strength of, concrete fill over joists.129 

steel joist floors. 11 

steel at high temperature. 6 

Strip steel production.132 

Structural steel, cost of.68-71 

fireproofing of..7, 106-109 

framing members...125-127 

method of production. 9 

necessity of fireproofing. 9 

Structural timbers, comparison with steel joists.167 

fibre stress.165 

maximum spans....165 

safe loading..166 

Suspended ceiling.. 97 

specifications for.124 

Steel lumber sections, various uses...149-155 

Table of board measure.168 

Temperature strength curve, steel. 6 

Terrazo flooring, weight of...161 

Ties, lateral for steel joists.55, 92 

Tile, hollow walls, weight of.160 

flat flooring, weight of._.161 

fireproofing structural steel.110 

Tire racks.153 

Tolerances. 12 

Truck frames. 150 

Tunnel shoring....151 

Ultimate strength, steel joists. 7 

U. S. standard gauge..170 

Various uses for National Sections...149-155 

Wall anchors for steel joists.86, 92 

Walls, masonry, weight of.160 

Water, weight of.161 

Web resistance. 34 

Weights of, steel joist.13-20 

steel joist floors.130 

strip steel.170 

building materials.160, 161 

various firesafe floor slabs.131 

Welding, steel joists.......133 

Widths of National strip steel._...169 

Wood joists, comparison with steel joists.8, 167 


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THE NATIONAL PRESSED STEEL COMPANY 


DISTRIBUTERS 

OF 

NATIONAL STEEL LUMBER 


Akron, Ohio.:.H. L. Thomas Co. 

Albany, Ala.Decatur Cornice & Roofing Co. 

Albany, N. Y.N. C. Clausen Architectural Iron 

Works. 

Atlanta, Ga.Austin Bros. 

Aurora, Ill.Garbe Iron Works. 

Baltimore, Md.....Chesapeake Iron Works. 

Bethlehem, Pa...Bethlehem Construction Co. 

Birmingham, Ala.Ingalls Iron Works. 

Boston, Mass.Boston Structural Steel Co. 

(Cambridge) 

Buffalo, N. Y.Buffalo Structural Steel Co. 

Cambridge, Mass.Boston Structural Steel Co. 

Cedar Rapids, la.Iowa Steel & Iron Works. 


Charlotte, N. C--Southern Engineering Co. 

Chattanooga, Tenn.Converse Bridge & Steel Co. 

Chicago, Ill.Duffin Iron Co. 

Gage Structural Steel Co. 


Holmes-Pyott Co. 

Kenwood Bridge Co. 

Union Foundry Works. 
Vanderkloot Steel Works. 

Cincinnati, Ohio.The General Iron Works Co. 

Cleveland, Ohio.The Van Dorn Iron Works Co. 

Columbus, Miss.Decatur Cornice & Roofing Co. 

Columbus, Ohio.The Fred A. Tarrier Co. 

I___ 


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THE NATIONAL PRESSED STEEL COMPANY 


National Steel Lumber Distributers.—Continued 

Dallas, Texas...Mosher Steel & Machinery Co. 

Dayton, Ohio.The Dayton Structural Steel Co. 

Decatur, Ill.Decatur Bridge Co. 

Denver, Colo.Robt. C. Cornett & Co. 

Minneapolis Steel & Machinery Co. 

Des Moines, la.Des Moines Steel Co. 

Detroit, Mich.Lewis-Hall Iron Works. 

Erie, Pa.Erie Steel Construction Co. 

Evansville, Ind.International Steel & Iron Co. 

Ft. Wayne, Ind.The Engineering Co. 

Great Falls, Mont.Minneapolis Steel & Machinery Co. 

Greenville, S. C.Decatur Cornice & Roofing Co. 

Hartford, Conn.J. C. Bidwell & Co. 

Houston, Texas.Houston Structural Steel Co. 

Indianapolis, Ind.Hetherington & Berner. 

Jacksonville, Fla.Decatur Cornice & Roofing Co. 

Johnstown, Pa—.Geo. J. Griffith Co. 

Kansas City, Mo.Kansas City Structural Steel Co. 


Kansas City, Kansas ..Kansas City Structural Steel Co. 
Little Rock, Ark.._.Bemberg & Sons Iron Works. 


Long Island City.National Bridge Works. 

Mansfield, Ohio.The Hughes-Keenan Co. 

Massillon, Ohio.The Massillon Bridge & Structural 

Co. 

Memphis, Tenn..„.Pidgeon- Thomas Iron Co. 

Meriden, Conn.National Bridge Works. 

f 

L--- 


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THE NATIONAL PRESSED STEEL COMPANY 


National Steel Lumber Distributers.—Continued 

Milwaukee, Wis.A. F. Wagner Architectural Iron 

Works Co. 

Minneapolis, Minn_Crown Iron Works Co. 

Minneapolis Steel & Machinery Co. 
Muskogee, Okla.Muskogee Iron Works. 

Nashville, Tenn._.Nashville Bridge Co. 

Newark, N. J.A. S. Reid & Co. 

New Orleans, La..„.Christopher & Simpson Iron Works 

Nashville Bridge Co. 

New York City.National Bridge Works 

(Long Island City). 

Norfolk, Va.Richmond Structural Steel Co. 

Oklahoma City, Okla. J. B. Klein Iron & Foundry Co. 

Omaha, Neb.Omaha Steel Works. 

Philadelphia, Pa.Belmont Iron Works. 

Pittsburgh, Pa...Taylor & Dean. 

Portland, Ore.Walter A. Scott Co. 

Providence, R. I.Providence Steel & Iron Co. 

Quincy, Ill.Michelmann Steel Construction Co. 

Richmond, Va.Richmond Structural Steel Co. 

Roanoke, Va.Roanoke Iron & Bridge Works. 

Rockford, Ill.A. C. Woods & Co. 

Rock Island, Ill.—.Rock Island Bridge & Iron Works. 

Rochester, N. Y.F. L. Heughes & Co. 

Salt Lake City, Utah ..Minneapolis Steel & Machinery Co. 

San Francisco, Cal.Walter A. Scott Co. 

% 


182 






















1 


THE NATIONAL PRESSED STEEL COMPANY 

National Steel Lumber Distributers.—Continued 

Scranton, Pa.Anthracite Bridge Co. 

Seattle, Wash.S. W. R. Dally Co. 

Spokane, Wash.S. W. R. Dally Co. 

Minneapolis Steel & Machinery Co. 

St. Louis, Mo.Christopher & Simpson Iron Works. 

St. Joseph, Mo.St. Joseph Structural Steel Co. 

Syracuse, N. Y.Syracuse Engineering Co. 

Tacoma, Wash.S. W. R. Dally Co. 

Toledo, Ohio.Geo. L. Kirby Co. 

Utica, N. Y.Utica Steam Engine & Boiler 

Works. 

Waukesha, Wis...Federal Bridge & Structural Co. 

Wheeling, W. Va.The J. E. Moss Iron Works. 


183 

















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